The Gundestrup Cauldron

Acta Archaeologica vol. 76, 2005, pp. 1–58 Copyright C 2005

Printed in Denmark ¡ All rights reserved ACTA ARCHAEOLOGICAISSN 0065-101X

THE GUNDESTRUP CAULDRONNew Scientific and Technical Investigations

by

S N, J H A, J A. B, C C, J G, P M. G,M H, A J, E B L, H B M, K M,

M-J N, S R, H S, Z A S, & T E. W

CONTENTSIntroduction Svend Nielsen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Previous Scientific Investigations Jan Holme Andersen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Technical Investigations – Work in Progress Erling Benner Larsen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Thickness of the Silver Parts Arne Jouttijärvi & Jan Holme Andersen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Metallurgical Examinations Arne Jouttijärvi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Lead Isotope Analyses Joel A. Baker & Tod E. Waight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Lead Isotope Provenance Studies Zofia Anna Stos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29The Eyes of the Faces Stefan Röhrs, Heike Stege & Katharina Müller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40Flow of Raw Materials Jan Holme Andersen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42Investigation of the Iron Ring from the Rim Arne Jouttijärvi & Helge Brinch Madsen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Analyses of the ‘Black Substance’ Jens Glastrup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46The Accelerator Dating Pieter M. Grootes, Marie-Josee Nadeau & Matthias Hüls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Bog Geological Investigations in Rævemosen 2002 Charlie Christensen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50Concluding Remarks Svend Nielsen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

INTRODUCTIONAmong the objects exhibited at the Danish NationalMuseum in Copenhagen the Gundestrup cauldronhas kept its outstanding position since it was foundmore than a century ago. This no doubt has to dowith the fact that we are facing ancient imagery notmet elsewhere. Moreover, the cauldron is entangledin questions, which have so far not been answered.

Accordingly, the literature dealing with the Gun-destrup cauldron is impressive and steadily increasing.Among Danish scholars who have dealt with the

Gundestrup cauldron, all of them several times,should be mentioned S. Müller, O. Klindt-Jensen andH. Norling-Christensen (Müller 1933; Klindt-Jensen1950; Norling-Christensen 1966), and E. Benner Lar-sen, who focused on the exiting history of the find(Larsen 1995). F. Kaul attempted to identify and datevarious attributes (Kaul 1995). He is also a strong ad-vocate of the ‘Thracian link’, even suggesting histori-cal contexts of manufacture. Among foreign scholarswho dealt with the Gundestrup cauldron within thelast generation, or so, could be mentioned R. Pittioni

2 Acta Archaeologica

and not least the important and thorough work by R.Hachmann, not to forget the recent and inventivestudy by F. Falkenstein (Pittioni 1984; Hachmann1990; Falkenstein 2004). In addition, a good manyshorter papers are to consider.

Yet, even when dealing with this wealth of litera-ture, it soon becomes evident that there are still manytopics that have not been studied, primarily due tolacking investigations. In particular, I refer to up-to-date scientific and technical research, whereas com-mon topics such as iconography, religion, origin anddating have been dealt with over and over again inthe literature – with highly divergent results. Today,it is possible, thanks to employment of a variety ofadvanced scientific methods, to illuminate many tech-nical questions. In a modern archaeological hand-book the possibilities presented are almost legion.

Certain comparative data, in particular when com-piled over decades, constitute a most important fieldof research. Thus, lead isotope analyses tell about thegeographical origins of metals, such as the silver andtin used to make the Gundestrup cauldron. Likewise,X-ray detecting techniques inform about the age andtype of the glass inlays used as eyes on the faces ofthe outer plates. Furthermore, it is possible to identifythe small amounts of apparently organic material,which is seen on the backsides of some of the plates,for instance, by employment of gas chromatography-mass spectrometry. Such identification has provedsuccessful, and the material is suitable for acceleratordating, when available in sufficient amount.

Also to be considered are the very small remainingquantities of soil on the backside of some of the plates.Is this soil foreign, or deriving from the RævemoseBog where the cauldron was once found? Possibly,pollen analyses or other kinds of investigations mayhelp to answer such and other questions. The pre-served section of the iron ring inside the silver rim ofthe cauldron should also be considered; this smallpiece of iron has almost been ignored or simply for-gotten in the discussion. Would it be possible toundertake an accelerator dating of the small carbonresidues of this piece of iron, maybe even to settlewhat kind of iron one is dealing with and thus illumi-nate its origin?

To the abovementioned investigations should beadded various kinds of metallurgical ones, such as

Scanning Electron Microscopy (SEM), and not leastinquiries about how the Gundestrup cauldron wasproduced departing from a technical angle. In short,many topics cry out for consideration. Indeed the pos-sibilities of employing such methods, as well as others,which might turn up during a future phase of re-search, were eagerly discussed for years among ErlingBenner Larsen, Helge Brinch Madsen, and the pres-ent author.

Right from the beginning our position was clear:not until much more was known about the Gunde-strup cauldron itself and its material aspects, so to say,would it be sensible to consider such intricate pointsas age, origin(s) and cultural setting(s) of this uniqueartefact. In our opinion, Danish scholars ought to in-itiate such labour simply for practical reasons; but atthe same time we were well aware that expertise fromabroad would be needed, too.

Thanks to generous economic support from theVelux Foundation and a very positive attitude fromthe National Museum it became possible to undertakethe desired investigations of the Gundestrup cauldronin 2002. These were carried out in a co-operationbetween The Royal Danish Academy of Fine Arts,School of Conservation, and the National Museum.For around half of this year the cauldron was re-moved from the exhibition and substituted by one ofthe existing excellent replicas. The original wasbrought to the Department of Conservation at theNational Museum, where a very thorough technicalinvestigation could take place, which was plannedand undertaken by E. Benner Larsen. The work wasfacilitated by the fact that, from a conservator’s pointof view, not considering ancient damages and wears,all parts of the cauldron remain astonishingly wellpreserved.

Sampling of various materials from selected areasmade up a considerable part of the work, which hadto be undertaken. Thus, no less than 45, 11, and 10samples of silver, gold (gilt) and tin, respectively, weretaken, employing a method which both excluded con-tamination of the samples and reduced the physicaloperations to an absolute minimum. ConservatorsClaus Gottlieb and E. Benner Larsen undertook thiswork. Two samples were taken from the iron core ofthe rim; conservator Peter Henrichsen carried out thiswork. For identification, geologist Ulrich Schnell took

3The Gundestrup Cauldron

Fig. 1. X-radiograph of the inner plate C 6575 showing details of traces from working tools. X-radiograph and digitalisation: Birthe Gottlieb,the National Museum.

four samples of the organic material mentionedabove, as well as 17 samples of the same material foraccelerator dating and further research.

The thin layer of soil on the back of some of theplates, to be found in concavities of the figures cov-ered with a thick layer of conservation lacquer, turnedout to contain charcoal particles, clay, diatoms, andvery fine-grained sand. In order to undertake furtheranalyses, these materials, quantitatively very small,were carefully washed out using solvents. It is ourhope that results of forthcoming analyses of these ma-terials will also prove successful.

Eventually, various samples were distributed to theparticipating scholars for further treatment, some ofwhich took place in Denmark, whereas other studieswere undertaken by scholars abroad. The results ofthese efforts are discussed in the respective sectionsbelow. It goes without saying that many new ideasturned up during the long period of investigation, notleast because several experts and colleagues were cur-rently consulted, including some from foreign coun-tries who were also invited to inspect the cauldron atclose quarters.

All parts of the cauldron were X-radiographed,which resulted in clear and crisp pictures making itpossible, e.g., to trace the working tools involved (Fig.1). The X-radiographing was carried out by conser-vator Birthe Gottlieb at the Department of Conser-vation, who also computer-scanned the X-radio-graphs in full scale at ultra high resolution for furtherstudy on a computer video screen.

A final point to be mentioned is an investigation,which took place in August 2002 in the Rævemose,northern Jutland, where the Gundestrup cauldron wasfound during peat cutting on 28th May, 1891; also thisinvestigation is discussed below. The idea was to in-spect the present conditions of the find spot, which isprotected, and to undertake geological investigations.In addition, it was attempted to find missing parts ofthe cauldron, i.e., one outer plate and the remainingsections of the rim, using metal detectors.

The following reports are submitted by most of thescholars who have participated in the work. Althoughsome of these reports remain preliminary, we believethat they all will be of interest to the readers of Acta

Archaeologica.


PREVIOUS SCIENTIFIC INVESTIGATIONSThe following survey of selected previous scientificand technical investigations is given in order to bringthe new investigations into perspective. This impliesextracts of some early analyses, hitherto unpublishedin English.

THE WORK OF SOPHUS MULLER

On arrival at the National Museum on the 2nd ofJune 1891, the outstanding silver find was at onceinterpreted as a dismantled cauldron with a doublesided upper part. Sophus Müller immediately set outto scrutinize the find including a general description,technical investigations, chemical analyses of the dif-ferent materials, and botanical investigations at thefinding place in the bog, as well as an investigation ofthe imagery in an attempt to place the cauldron intoan archaeological context. Impressively fast, S. Müllerwas able to publish the resulting observations in hispublication on the Gundestrup cauldron (Müller1892), which remains basic to anybody dealing seri-ously with the subject. Unfortunately, he only in-cluded a rather short resume in French in his bookso that foreign scholars have had a hard time gettingto know about his important results.

General description

On accession, the 17 parts of the find were assignedInv. nos. C 6562 through C 6576 (see also Fig. 5),whereas Müller used the Roman numerals VIthrough XIV in his book to designate the decoratedplates. Müller’s description of the parts can be sum-marized as follows:

A voluminous bowl, 21 cm in depth and c. 69 cmin diameter with a circumference of 216 cm at thetop. – Inv. no. C 6562.

A circular plate decorated with embossed andchased motifs gilded all over on the front. The centralmotif depicts a recumbent bull with the head raisedhigh. The diameter of the plate is c. 25 cm. – Inv. no.C 6563 (Müller, plate XIV2).

Seven rectangular plates decorated with embossedand chased motifs on their convex sides, partly gilded.The central motif of each plate depicts either a maleor female half-length portrait with different humanand animal figures at their shoulders or raised arms.

The length of the plates at the bottom edge variesfrom one plate of 24.5 cm, one of 24.75 cm, four eachof 25.5 cm to one plate of 26 cm. Their heights are21 cm except one, C 6569, cut down to 18.5 cm. –Inv. nos. C 6564–C 6570 (Müller, plates XIV1, XIII1,XIII2, XII2, XI2, XI1 & XII1).

Five longer plates without gilding and with the mo-tifs on their concave sides. Different sceneries withhumans, animals and fabulous monsters etc. composetheir motifs. The length of the plates at the bottomedge varies from two plates of 40 cm to ones of 41,43 and 44 cm each. Their heights range from 20 to21 cm. – Inv. nos. C 6571–C 6575 (Müller, plates IX,X, VIII, VI & VII).

Two pieces of tubing curved to the same diameteras the bowl. They are slit at the bottom, c. 2 cm incross-section and approximately of the same length asone of the smaller plates. One of the tubes en-compasses pieces of an curved iron rod. – Inv. no.6576.

The parts are fully shaped by hammering and neat-ly worked with a great deal of skill. The bowl is thinlyraised silverwork of uniform thickness. The rectangu-lar plates are somewhat thicker than the bowl and thecircular plate even more so, especially at its edge. Allmotifs on the plates are raised from the back andchased from the front, and in the concavities on theback there are small remains of a black substance.The rather thick gilding on the front of the circularplate and the smaller rectangular plates seems to havebeen applied in a cold state as it is only rubbed orpressed onto the silver. All plates and the bowl showsigns of soldering around the edges.

The cauldron was by no means new when it wasdeposited in the bog, but showed signs of considerablewear and damage, though not enough to make it use-less. Many protruding areas are more or less worn,especially on the outer plates where most of the gild-ing is worn off leaving only remains in the concavitiesand corners. The ears and horns of the bull on thecircular plate are missing. The bottom bowl isscratched and scraped in several places both on theoutside and inside and it has an irregular broken hole,8–10 cm with outspread fractures, in the bottom. Allin all, Müller states that the cauldron showed signs ofhaving been dismantled into its single parts by the useof force and that especially the outer plates had be-


come somewhat battered and pierced before the indi-vidual pieces were placed in the bowl and carefullydeposited on the surface of the bog.

Chemical analyses

S. Müller at once had the metal analysed by the Coinand City Assayer of Copenhagen, S. Groth, in orderto establish its value and calculate the reward to thefinders. The report of 3rd August 1891 by S. Grothdeclared all parts to be of silver, 970‰ sterling worth,and the overall weight to be 8,885 grams. The goldcontent of the silver was set to c. 3‰, and togetherwith the gilding covering some of the plates the over-all gold content was estimated to be 5‰. The metalused as solder was determined as tin. (Report in thearchives of the National Museum; Müller 1892, 41;Larsen 1995, 191).

Further samples were chemically analysed by V.Stein’s Laboratory in Copenhagen and in their reportof 23rd April 1892 V. Stein gives some interestinginformation (report in the archives of the NationalMuseum; Müller 1892, 41; Larsen 1995, 196f):1) The solder was proven to be of 97.6% tin and

2.4% silver.2) The brown material taken from the interior of one

of the silver tubes was proven to be iron oxide(rust) covering a solid core of metallic iron.

3) The black substance from the concavities of theback of the plates ‘‘... was of an organic naturethat burnt with a bright, strongly soothing flameby combustion, leaving behind an almost negli-gible inorganic residue. The substance was onlypartly dissolvable in alcohol or ether, but very eas-ily and completely in chloroform only leavingsome fine black particles (carbon) behind.’’ – Theconclusion being that the substance consisted of aresin (maybe birch resin) and wax. However, it wasnot possible to give the chemical composition pre-cisely due to the small size of the samples.

In his publication, Müller commented on the resinthat the dark, hard substance apparently had beenapplied in a soft or fluid form onto the backs of theplates in several places where the motifs were stronglyraised in order to strengthen the plates while theywere worked over from the front. Further, he men-tions that this technique of employing resin was

known in ancient North and Central Europe, but notin the South, neither in the works of Prehistory northe Roman culture, though one example was knownfrom the Gallo-Roman area. Here the black sub-stance taken from the back of bronze masks fromCompiegne burned with a flame like that of resin(Müller 1892, 42).

It can be stated that Müller has done what he couldto analyse the find by the means available at the time.Since Müller, no one has questioned that the blacksubstance could be anything other than resin and itis quoted as such in many publications. Today, muchmore sophisticated techniques of analyses are at handand what Stein’s Laboratory in 1891 showed to beresin, the new analyses of 2002 with the aid of gaschromatography – mass spectrometry has proven tobe beeswax (see J. Glastrup’s section below).

Construction and form of the cauldron

Assuming the upper part of the cauldron to have beenassembled of inner and outer plates with pictures fa-cing both inwards and outwards, the five concaveplates being placed on the inside and the seven con-vex smaller plates placed on the outside with aneighth plate missing, Müller went on to reconstructthe cauldron. Comparison of measurements betweenthe upper circumference of the bowl and the overallwidth of the five inner plates showed a gap of c. 2 cmbetween each of the plates when distributed evenlyaround the top of the bowl. Similarly, the seven outerplates also left a gap of c. 2 cm between each of theplates to match the circumference of the bowl as-suming there had been an eighth plate of a similarsize as the other ones. This, together with the 1–2 cmbroad traces of tin soldering around all borders of theoutside of the square plates and on the top of thebowl on both sides, indicated that the cauldron hadbeen assembled with soldered on and now missingmetal bands, 4–5 cm in width.

A further proof of the upper part of the cauldronbeing double is four holes, assumed by Müller to haveserved for rivets, which in two positions have beendriven through the sides of the cauldron. On the in-ner plate C 6572 there had been inserted a rivet nearthe upper edge to the left that had joined the outerplate C 6570 near the upper edge, slightly to the rightof the central head. Likewise, a rivet had been driven


Fig. 2. Pencil drawing of the Gundestrup cauldron by J. MagnusPetersen on the basis of Sophus Müller’s reconstruction 1891.

Archives of the National Museum.

from the outside somewhat further down from theupper edge through the hair on the central head ofthe outer plate C 6567 and piercing the inner plateC 6575 in front of the head of the middle bull. Theposition of these holes, their edges and the in- andoutward curving of the metal clearly showed thatthese plates had been placed back to back. Accordingto Müller (1892, 38 & 40) the two rivets, now lost,may well have served to fasten two suspension ringsopposite each other like those known from similarcauldrons of bronze or iron. Apart from the four rivetholes only two other (very) small holes in the upperright corners of the outer plates C 6568 and C 6566can be seen. Müller attributed these to be part ofsome ancient repair.

As for the rim of the cauldron the two slit silvertubes fit the top edge of the plates. The enclosedpieces of iron in one of the tubes must have been partof a thick iron ring to strengthen the upper part ofthe cauldron. Müller assumed eight such tubes tohave existed, each meeting the next one above thecentral heads of the outer plates. Here the parts wereconnected over the rim, front to back, on the outsideby metal bands of which traces of tin soldering clearlycan be seen at the top of the plates and on top ofsome of the central heads together with other markson the ends of the silver tubes. Small expansions in

the middle of the slits in the bottom of the two tubes,indicate room for the metal bands connecting theplates vertically and further indicate that these bandswere flat.

According to Müller (1892, 39) only one order inthe arrangement of the inner plates was possible,given the position of the traces of soldering from themetal bands across the rim from the top of the innerplates to the top centre on each of the outer platestogether with the position of the above mentionedrivet holes opposite each other. The order being fromleft to right: C 6574, C 6575, C 6573, C 6571 and C6572, or, with Müller’s numerals, VI, VII, VIII, IXand X, which is why he used this sequence of thenumbers in his book and plates of phototypies. Subse-quently, the two outer plates C 6567 and C 6570 fellinto place as a consequence of the rivet holes beingopposite to each other. In this way, only the positionof the five remaining outer plates became uncertain.Assuming the missing outer plate depicts a femaleportrait, there would have been four female and fourmale heads all together, probably placed alternatingfemale-male.

The cauldron was assembled by conservator V.F.Steffensen using small clamps of silver and placed inits own showcase in the fifth room of the exhibitionin the late summer of 1891 (Müller 1892, 36; Larsen1995, 136f). So Müller must have worked very fastduring the summer, drawing all of his conclusions re-garding the construction of the cauldron. After beingassembled, the cauldron was drawn by J. MagnusPetersen in a pencil drawing later used as a model forthe chemotypie printed in Müller’s book (Fig. 2). Herea part of the arrangement of the outer plates can beseen as well as the placing of the silver tubes. Differentscholars have proposed several arrangements of theorder of the plates since then.

As exactly matching traces of soldering show, thecircular Bull plate has been soldered to the bottom ofthe bowl. Later E. Benner Larsen has further provedthis, even that the plate was positioned slightly askewfrom the middle, covering the irregular hole in thebottom (Larsen 1987, 404 Figs. 24 & 25).

The pupils of all the eyes of the portraits on theouter plates were cut out. Müller states that in fivecases an inlaid ball-like, reddish blue glass (flux) waspreserved, but this must be a misprint as only four


can be seen on the phototypies in his book, and thesefour still exist. For comparison, Müller mentions anddepicts two bronze heads from Compiegne with cut-out eyes, of which one had inlaid eyes of glass, andone silver mask from Brissac with cut out pupils, allresembling those on the cauldron in style (Müller1892, 58). On page 54 in his book, Müller states thatthe glass eyes were fastened with metal from behind,but on page 41 he also mentions them in connectionwith the analyses of the dark substance found on theback of the plates. This must have led to some misun-derstanding by certain readers, because O. Klindt-Jensen (1961, 7, Fig. 3) and A. Villemos (1978, 80)both state that the eyes are fastened with lumps ofresin, while the new investigations of 2002 has proventhese fastenings to be of tin covered with a layer ofcorrosion.

The artisans

Sophus Müller brought special attention to the factthat the cauldron was not the work of one single per-son. The inner plates C 6574 and C 6571 togetherwith the outer plates C 6567 and C 6565 would bethe work of one person judging from the similarity ofstylistic details and differences from the other plates.Müller’s stylistic arguments for this view shall not begiven here, except that on the working of patterns onthese plates a circular punch has been used, which isnot used on the other plates. Similarly, the outer plateC 6569 is the sole work of another artisan who, judg-ing from the details of the working, has only done thisone plate. The rest of the plates must have been thework of one or possibly two more artisans. Müllerconcludes that the cauldron was the collective workof a group of artisans with similar skills and a mutualdirection of art, resembling a style that at a certaintime had flourished in a certain place.

RECONSERVATION OF THE CAULDRON

In connection with a reorganisation and refurbishingof the prehistoric collections of the National Museum,a considerable part of the collections was reconservat-ed. Thus, in 1977, the Gundestrup cauldron was dis-mantled and transferred to the Department of Con-servation where the conservators Ann Villemos andClaus Gottlieb undertook the conservation work.

A layer of lacquer applied to the surface of thecauldron to protect the silver from the noxious influ-ence of air had become brownish with age and wasobscuring the gilding, among other things. Unfortu-nately, no information regarding the agents used inthe conservation of the cauldron in the course of timecan be found in the archives. Having carefully re-moved the layer of lacquer using solvents, the singleparts of the cauldron were cleansed for oxidation witha solution of Rochelle salt and rinsed with distilledwater. The plates were only treated from the front,taking care not to damage the residues of organic ma-terial still found on the back of the plates. A gooddeal of ‘resin’ and ‘bog material’ was still present, in-dicating that the plates have apparently never beencleaned on the back (Villemos 1978).

After the cleaning, the silver now stood out quitebrightly and the details of the decoration showedthemselves, when subsequently each single part wasstudied by microscopy. It was now possible to registerthe extension of the gilding on the outer plates andthe Bull plate. On some areas, the gilding had flakedoff and it was obvious that where the gold once hadbeen applied, the surface of the silver was rough andnot smooth as on the surrounding bare areas. Also, itwas possible to see areas of the gilding, e.g., on plateC 6570, where the borders of the gilding are hard torecognise. On the other hand, silver salts have in timecovered some areas of the gilding, so this is hard tosee, e.g., on plate C 6564. However, attempts to re-move this layer electrolytically with potassium cyan-ide turned out to be impossible without loosening theunderlying gilding so the extension of the latter in thiscase is not quite known. The extension of the gildingresulting from these observations is shown accentu-ated on Figs. 3–11 in Villemos’ publication of 1978.After the reconservation, the parts of the cauldronwere relacquered with Incra laquer and reassembledto be relocated in the exhibition in a new showcase.

THE WORK OF E. BENNER LARSEN

While the cauldron was still dismantled and simul-taneously with the above-mentioned investigation,Benner Larsen from the School of Conservation hadthe opportunity to undertake documentation andidentification of toolmarks deriving from the manu-


facture of the cauldron. Especially pressmarks frompunches used to decorate detail patterns in the surfaceof the embossed and chased motifs and their back-grounds could be traced to act like fingerprints of theindividual tool. The results of this investigation turnedout to be a major pioneering work (Larsen 1985;idem 1987).

Based on the distribution of toolmarks derivingfrom punches Larsen was able to document 15 differ-ent punches, that could be divided into three distinctgroups with no overlapping between the tools, plus afourth group consisting of two outer plates (C 6569and C 6570), bearing no marks of punches. The firstgroup of toolmarks are found on two outer and twoinner plates, designated Toolset I, the second groupof toolmarks are found on three outer plates and threeinner plates, designated Toolset II, while the thirdgroup of toolmarks are only found on the circular Bullplate and is designated Toolset III.

Amazingly, or perhaps not surprisingly, there is ahigh degree of accordance between Larsen’s techni-cal investigations and the grouping resulting fromthe stylistic studies by S. Müller, except for the two

Table 1. The result of E. Benner Larsen’s investigations of toolsets used to decorate the plates in relation to the stylistic and iconographicalresults of different scholars. The table is based on the works of E. Benner Larsen and R. Falkenstein (Larsen 1985, 571 Table II; Falkenstein2004, 77 Abb. 15).

outer plates C 6569 and C 6570 which do not bearmarks of punches. Also, Larsen could show similarcoincidence with the earlier stylistic studies of O.Klindt-Jensen and G.S. Olmsted (Klindt-Jensen1961; Olmsted 1979). Other scholars have later usedthe important observations of Larsen in their ownstylistic and iconographical studies (e.g., Hachmann1990; Kaul 1991; Olmsted 2001; Falkenstein 2004).Table 1 summarizes the grouping of the plates byeach scholar.

Finally, another important work by Benner Larsento be mentioned is his publication from 1995 on theGundestrup cauldron. Based on well-documentedsources from many different archives and a wealth ofpictures, he tells the story of the find. Also, he presentsimportant information about the seven electroformcopper replicas of the cauldron made from 1892 to1967 and the one replica. of the plates made of gyp-sum in 1961. This is supplemented by informationabout the scientific investigations and analyses carriedinto effect by Müller that are quoted in this papertoo. Unfortunately this work has only been publishedin Danish.


FINAL REMARKS

One may wonder about the ‘crude’ way the metalbands have been fastened to the plates and especiallyonto the top of some of the central faces on the outerplates. This might indicate that some other personthan the original artisans did this work at a later stage.Still, the plates do originally allow room for some kindof framing at their undecorated borders. Likewise,one may wonder why the so-called rivet holes areplaced so that one of these has been driven throughthe forehead of the figure on the outer plate C 6567.And surprisingly, none of the above-mentionedscholars have noticed that the three outer plates ofMüller’s artist 3 and Larsen’s Toolset II all have sur-face gilding as a background around the central fig-ure, a point that supports this grouping.

To conclude this survey, it may be appropriate topoint out that the important work of Sophus Müllerformed the foundation on which all later scholarshave built their work and further to quote the open-ing part of his work on the Gundestrup cauldron(1892, 36 my translation): ‘‘... Especially when facingsuch a piece, there is good reason to stop and wait.One cannot unpunished attempt to force the investi-gation beyond the borders set by contemporaryknowledge, and equally, it would be erroneous by fu-tile accumulation of material, which is not strictly rel-evant, to hamper and burden future considerations.When this strange find for the first time should beintroduced into literature it ought to happen in a waythat it will not once in the future be necessary first toclear an obstructed position, in order to show the wayon the basis of larger knowledge and new finds to thefull and right understanding.’’

TECHNICAL INVESTIGATIONS –WORK IN PROGRESSPRELIMINARY INVESTIGATION IN 1977

My preliminary investigations of toolmarks and sur-face textures on the Gundestrup cauldron wereundertaken in 1977, when it was re-conserved at theDepartment of Conservation at the National Mu-seum. On that occasion, I had only limited time forthe work, but I had the opportunity to study the tool-marks when the conservation lacquer, which had cov-ered the parts for many years, had been removed.

Fig. 3. Silicone rubber mould from the inner plate C 6571. Tool-marks have in this way been transferred from concavities in thesurface of the silver to convex impressions in the rubber surface.The motif is a leaf ornament. To the right inside the contours ofthe leaf a fine line shows the use of a scriber to lay out the designbefore tracing the contour line. Characteristic marks from thetracer are clearly seen in the curves. A dot punch has been used

for the background decoration. Photo: E. Benner Larsen.

As time was short, I confined my investigations toselected areas where punches had left clear marksduring the final chasing of the repousse work. I mademoulds of areas of particular interest employing aspecial silicone rubber (Fig. 3). The toolmarks re-corded (in reverse) by the moulds were studied underthe microscope and selected areas of them werephotographed using a Scanning Electron Microscope(SEM). In this way, the various punches, which hadmade the marks were identified and documented, asthe individual micro geometry of the tools used wasclearly visible (Larsen 1985; idem 1987). Thus theSEM photographs could be compared and marks offifteen different punches could be identified in threegroups, Toolsets I with punch marks A–F, Toolset IIwith punch marks G–K, and Toolset III with punchmarks L–O, respectively (Fig. 4). Two outer plates, C6569 and C 6570, could not immediately be associ-ated with any of the three groups, because these twoplates did not bear any marks of punches.

Later analyses of other toolmarks like, for instance,planishing punches and tracers to delineate the baseof high relief, which I carried out in 1991, led to anew grouping of the individual parts, see Table 2 and


Fig. 4. Diagram showing three different sets of punches used in thedecoration of the Gundestrup cauldron. The column on the leftgives the inventory of each panel. The rubric above with letters Ato O indicates the 15 different identified marks of the punches. E.

Benner Larsen del.

Fig. 5 for references to the parts of the cauldron.Outer plate C 6570 could now be associated by marksof planishing punches with Toolset II, whereas outerplate C 6569 could not be linked with Toolsets I, IIor III. This plate is in many ways quite different fromall other plates not only from a stylistic point of view.A scar in the face of a planishing hammer has leftmarks in the surface of the silver. These scar marksare not seen on any other plate. Outline punches usedto delineate areas at the base of high relief – especiallyaround the head, the arms and the beard of the god –cannot be linked to any outlying punches used onother plates. These specific tools make up Toolset IV.

The huge bowl C 6562, 69 cm in diameter, re-mains a true masterpiece of ancient hammerwork(Wilson 1978, 151ff) whose point of departure was aningot weighing c. 3.74 kg of very pure silver. Themaking of the huge bowl and the silver tubes requireda number of different raising hammers and stakes ofdifferent weights and shapes. Some of the hammersused may even have been of organic material, e.g.wood or horn mallets. A scar in the face of a plan-ishing (steel) hammer can be traced over large areasof the outside of the bowl and scraper marks are seenas well on its inside. The remaining sections of therim of the cauldron, two curved silver tubes, represent

a very demanding task technically similar to the rais-ing of the bowl. They also required a specially madeshaping block – probably made of wood – and nar-row faced hammers (collet hammers) used in raising,suited to form deep curves. The tools used when mak-ing these parts are listed as Toolset V. Finally duringthe forging of the iron core of the rim special ham-mers, chisels, bottom swage and anvil were needed,Toolset VI.

Table 2. The results of the analyses of tool marks show in the leftcolumn the identification of three sets of individual tools used oneleven of the decorated plates. Two plates, C 6569 and C 6570,could not be linked to any of the three groups of toolsets since theybear no marks of punches (Larsen 1985, 571; idem 1987, 401).Later analyses in 1991 where other kinds of tool marks werestudied, e.g. planishing punches, led to a new grouping listed in thecolumn to the right. It is worth noting that the outer plate C 6569is not linked to Toolset I, II, or III but forms a ‘‘new’’ Toolset IV.Within Toolset V we are dealing with hammers and stakes of differ-ent shapes and weights. Hammers of organic material may alsohave been used when raising the huge bowl and the two tubes forthe rim. And finally forging tools like hammers, bottom swage,chisels and anvil were used to make the iron core of the rim of thecauldron, Toolset VI. All tool marks deriving from the forging pro-cess have naturally disappeared due to heavy corrosion of the iron.


Fig. 5. These drawings intend to remind the reader of the 17 partsof the Gundestrup cauldron. Top the bowl; below to the left theseven outer plates; to the right: the Bull and below it the five innerplates. Under these are two tubes and a small fragment of the ironcore from the rim. To avoid confusion the various parts are referredto using the original ‘C’ numbers of the National Museum. Thesilver tubes and the iron fragment were earlier registered underone number (C 6576); an A, B and C has been added. For anequation of these numbers with other designations, see e.g. R.Hachmann (Hachmann 1990, Abb. 14 and Abb. 15). Collage: E.Benner Larsen del. Based on drawings by E. Rondahl 1893, after

Steenstrup 1895.

NEW TECHNOLOGICAL INVESTIGATIONS 2002

During the investigation of 2002, it was possible tocontinue with my previous line of research. (Larsen1985; idem 1987; idem 1995). Thus it became poss-ible to undertake a thorough documentation includ-ing exact weighing (see Table 3), measuring of thick-ness, and drawing to full scale of the outline of all theindividual parts without the distortion of perspectiveresulting from the curving of the plates and bowl,which is present in all previous drawings and photo-graphs. Subsequently, on these new drawings, tool-marks, remains of tin solder, and marks of workman-ship from the shaping of the plates were recorded aswell as a variety of other observations, for instancethe delicate design of the motifs before their chasingwas begun (Wilson 1978, 33 and 44; Oldeberg 1966,167ff).

All the fronts and backs of the plates were exam-ined under the microscope. Hundreds of photographswere undertaken to document macro-details. Selectedareas were documented by silicon rubber moulds,which will later be examined by SEM. The mouldswill also be used to document in three dimensionsand to produce electroform replicas. Several of thetechnological investigations as well as researches intocraftsmanship were carried out along the lines de-scribed by Lowery, Savage and Wilkins (Lowery et al.1971).

The new observations and documentation of tool-marks indicate that more silversmiths than has hith-erto been thought may have been involved whenmaking the cauldron. Preliminary analysis of the newresearch on the Bull plate (Fig. 6 & p. 58), for in-stance, has revealed that at least three different setsof punches were used. In the following, numerals in


Fig. 6. The Bull plate C 6563, 25 cm in diameter, from the bottomof the cauldron – a masterwork of repousse work originally gilt onthe whole surface. Recent studies of toolmarks show that differenttools probably in different hands have been involved in its making.On the photo the inserted numerals 1 to 10 are used as referencesin the text to observations of details. At last three different handshave thus been involved – maybe even more. In the future workwe have to reconsider the grouping of tool marks and surface tex-tures. For better study of details see the enlargement of the Bull

plate p. 58. Photo: E. Benner Larsen.

brackets are used for reference to areas of special in-terest on Fig. 6. This impressive part of the cauldron,with its outstanding execution of the bull figure inhigh relief (1), stands out artistically in comparisonwith other decorations on the cauldron. Is it the mas-ter of the workshop himself who executed this verydemanding repousse work in an extraordinary highrelief? As to style and workmanship, there is a closeconnection between the bull and the dog (2) lying flaton the stomach under the bull with four outstretchedlegs. The dog and the bull differ completely from allother motifs on the Gundestrup cauldron. A differenthand made man with the sword (4) over the bull’sback – was it done later? The sword fighter, deador alive, in attitude and technical execution is almostidentical with two other figures on two outer plates C6564 and C 6570. Two other dogs (3 and 5) alsostand out from all other motifs on the cauldron.

The delicate tracing of the bull’s body was carriedout with a C-punch, i.e. punch O, Toolset III. Theneck and mane of the bull was executed with a tracerin a beautiful pattern, but it looks as if this fine chas-ing stopped and was completed by another hand withother tools. The right foreleg of the bull (9) was fin-ished by chasing with a small, almost rectangularpunch, punch N of Toolset III, and not as might beexpected, with the C-punch which was used on therest of the bull’s body. The surface of the hide on theleft side of the bull’s head, was chased with the sameC-punch as that used on the bull’s body, see Fig. 7(A) whereas quite another tool, a fine tracer used asa punch, was used on the right side of the bull’s head,

Table 3. For the first time, all parts of the cauldron were weighedcorrect to 0.1 g. Sophus Müller gives the total weight to 8,885 g(Müller 1892, 41). The total weight today is 8,838.6 g includingthe weight of the fragment of the iron core from the rim. Thisdifference of 46.4 g might make out the weight of a second pieceof iron core from the rim, which is now missing.


Fig. 7. The bull’s head seen in profile. The neat chasing of the left side of the head (A) was carried out with the same C-punch as was usedon the body of the bull, see Fig. 7, punch O. On the right side of the bull’s head (B) a small tracer has been used as a punch instead of theC-punch used on the left side of the head. For unknown reasons the chasing was left unfinished – until another hand using a quite differenttool completed the decoration. This peculiar change of tool is also seen on the right foreleg (Fig. 19, 9) where a small, almost rectangular

punch was used instead of the C-punch. Photo: Lennart Larsen.

see Fig. 7 (B). The same tracer was used on the furof the dog (3) above the shoulder of the bull.

The rolling or dead dog (5) shows the supreme skillof the master in a light moment, Fig. 8. It is fascinat-ing to see the virtuosity with which the C-punch, theonly punch used, danced over the surface of the silver,creating this unique small masterpiece. Richard Sav-age, having studied the little dog, made the followingcomment (personal communication): ‘‘To me, thesmall dog shows the actor offstage, out of makeup fora moment, alone or among his peers, before he sayswearily ‘OK, here we go again. Let’s give the buggerswhat they want’. Of course, once he gets back onstage, whatever magic he has takes its old grip, andhe knows God working through him again; but in thislittle dog we glimpse the vision which brought ourartist to a calling in which he may well have foundmuch of his work tedious, if materially rewarding, andwe remember the people and creatures who lurk andplay in the margins and initials of medieval manu-scripts.’’ Maybe the little dog was added later – or isit perhaps actually the ‘signature’ of the master him-self? Or are we looking at the end of a bullfight or abull hunt, with the bull dying among his tormentors,those whom he has killed or injured, and the survivorstriumphant?

The plant motifs on the bull plate are varied bothas to design and workmanship. It looks as if threeindividual silversmiths each made his own part of theplant ornaments. This is also the case when looking

at the working of the background of the plate, whichwas begun on small areas at four different places afterwhich the process came to a halt and was left unfin-ished. Around the tail of the bull (6) this backgroundornament was carried out with the same C-punch aswas used on the body of the bull and between theright foreleg and left backleg (10) the same C-punchwas used to start a background decoration. Betweenthe forelegs of the bull (7) it was carried out with thesame tool as was used on the right side of the bull’shead. In front of the little dog (3) and between themotifs with leaves, it was started using a small dot-punch, punch M of Toolset III (8).

The recent investigations, in which the marks notonly of punches, but also of other tools, are studiedindicate that at least three, and perhaps five or sixpersons, were involved in the making of the bull plate,and it is probable that more silversmiths than hashitherto been suggested were involved in the produc-tion of the cauldron as a whole. Thus one may im-agine that the various steps of production rangingfrom the initial melting of silver into ingots, throughthe manufacture of sheet silver, design, repoussework, chasing, the making of the bowl and gildingetc. were divided between specialists. It is well docu-mented that the craftsmen were not of equal skill.What is clear, however, is that we are facing a well-equipped and well-organized workshop with access toa good many different tools. All work on the platesmay be termed technically sophisticated although the


Fig. 8. Silicone rubber mould of the small crouching or dead (?)dog under the back legs of the bull (see Fig. 19, 5) chased usingonly the C-punch. The measure from ear to tail is 34 millimetres.

Photo: E. Benner Larsen.

style is sometimes naive. It may be argued that a mas-ter led the workshop in which craftsmen with unequalskills were employed.

ASSEMBLY OF THE CAULDRON

R. Hachmann (Hachmann 1990, 578) suggests thatthe Gundestrup cauldron was assembled, and thussoldered, twice. I have not found any evidence to sup-port this, but it can be documented that the solderingof two outer plates was adjusted. To the left on theouter plate C 6565 two different significant traces ofsoldering can be seen, c. 10 mm from each other (Fig.9), and on the outer plate C 6568 there is yet anotheradjustment of the soldering which covers the loweredge and c. 5 cm up along the right side. These ad-justments were probably undertaken to make the in-ner and outer plates fit together back to back with thebottom and the iron core at the rim of the cauldron.

The soldering together of the individual parts ofthe cauldron was a Sisyphean task. The tin usedflowed out of control over large areas of all the partsof the cauldron. Hence, there is a marked contrastbetween the professional craftsmanship of the silver-work and the clumsy tin soldering. This may be dueto the fact that the tin soldering that the silversmithsused was a technique new to them. It should be notedthat other cauldrons with an iron ring from the time

Fig. 9. On two different outer plates the soldering were adjusted inorder to correspond with the circumference of the silver bowl.Outer plate C 6565 shows to the right the outline of the two differ-ent solderings. The inner line (A) c. 21 mm from the edge indicateswhere the silver band was soldered. The distance between the twosolder lines is c. 10 mm at the lower right of the plate (B). Solder

mark C is refered to in Fig. 12. Photo: E. Benner Larsen.

about the birth of Christ were riveted together withno use of solder.

Examination of the iron core of the rim shows thatthere are considerable remains of tin solder on theinside of the core, which is V-shaped in section. Inthe traces of soldering on the bottom of the cauldron,there are 5 small holes with a diameter of c. 1 mm,


Fig. 10. Along the upper edge of the silver bowl five small holes (c.one mm in diameter) are documented (A). These small holes havebeen made with a mutual distance of c. 44 cm between the holes.All the five holes are placed c. 5 mm from the edge of the bowl.Through one hole I have passed a copper wire (B) to demonstratethat the holes probably served as fix points where drawn wire mighthave been fastened during the assembly of the cauldron prior to

soldering, see also Fig. 11. Photo: E. Benner Larsen.

evenly spread along the upper edge of the bottom,see Fig. 10 (A). A similar number of small holes canbe seen on the upper edges of both outer and innerplates. These small holes may have helped to fastenthe individual parts with a metal wire, which was pull-ed through the holes, see Fig. 10 (B). This way oftemporary fastening prior to soldering is still generallyemployed among present day silversmiths. The firstmost safe and stable mounting of the outer and innerplates could be achieved by placing all the individualplates upside down in the V-shaped groove of the ironcore of the rim. Thus the plates could be fastened inthe position wanted with metal wire. In this way, itwould have been relatively simple to solder all theplates together with tin in the groove (see Fig. 11).

The finishing of the soldering work was a long anddemanding labour. The craftsman tried to clean the

Fig. 11. A cross section shows how the outer and inner plates mighthave been mounted – upside down, fixed in the groove in the ironcore and held in position with drawn wires twisted around the iron

core prior to soldering. E. Benner Larsen del.


Fig. 12. The original positions of the inner and outer plates, basedon their measurements and the solder – and scraper – marks.White arrows on either side of the stippled line indicate correspond-ing solder marks on inner and outer plates marked with a square(see also Fig. 9, C). The larger arrows A, B and C, D indicate therivet holes marked with a black dot which show the exact relativepositions of the plates C 6570 and C 6572 (A, B) respectively C6567 and C 6575 (C, D). It is likely that two solid handles weremounted there. A three-dimensional image of the interlinking of all decorated

plates is easily made from a photocopy of this illustration. Fold along the

stippled line and glue together front to back and then bend and glue together at

the ends to form a cylinder as shown in Fig. 13. E. Benner Larsen del.Based on E. Rondahls drawings 1893.

flows of tin from all the individual parts of the caul-dron. This was done mechanically using variousscrapers, which were used forcefully on large areas ofthe delicate silverwork. The traces left, which are easyto recognize, were made by scrapers of various widths(Untracht 1975, 127), and are helpful in any attemptto understand the construction of the cauldron.Measuring and documentation of all traces of sol-dering – amounting to 14.6 metres long – has con-siderably helped our understanding of the mountingof the individual plates. Four holes of c. 4 mm diam-eter for rivets in two inner plates and two outer platesrespectively fit together two by two, inner plateagainst outer plate. Thus, from rivet holes, andmeasuring and documentation of soldering traces (seealso Fig. 9, C) and scraper marks, it is possible toestablish the individual position and connection of theindividual plates, see Figs. 12 and 13, which is essen-tial to any study of the style and iconography of theimagery of the Gundestrup cauldron.

The silver bands, which held the individual partsof the cauldron together, are now all missing. Exami-nation of traces of solder, however, show that thebands were profiled, since impressions of the profilingcan still be seen in many traces of solder along theedges of the plates. The silver bands were 4.2 cmbroad, with a total length of c. 7 m.

Of the eight curved silver tubes, which once cov-ered the iron core of the rim, only two have survived.Each of the tubes was made individually and subse-quently sprung onto the iron core. Traces of solderingand scraping also show that the junctions between thetubes were masked with solid profiled tubular silvercovers of slightly larger diameter. Each junction


Fig. 13. A three-dimensional model of the original position of innerand outer plates shows how the silver panels interrelate. The largerwhite arrows are pointing out the rivet holes C and B. These holesare positioned exactly opposite to one another just under the rimof the cauldron and two rings or handles were probably mountedhere. Model and photo: E. Benner Larsen, based on E. Rondahl’s

drawings 1893.

centred and soldered above the repousse heads ofouter plates. A point, which is significant in ourunderstanding of the planning of the cauldron’s uni-fied architecture. The carrying rings were probablyfixed in two of these solid silver mountings and se-cured with two solid rivets, Fig. 12 AB and CD.

WHAT THE BACK OF THE PLATES CAN TELL

Hardly any scholar has ever cared much for the‘backs’ of the plates, which are most informative. Forinstance, toolmarks tell a great deal about how thesheet metal was produced. Besides, in the concavitiesof the backs of all plates scattered remains of a darksubstance can be seen (Fig. 14), which has been iden-tified as beeswax and is discussed in a separate sectionbelow. No doubt this material acted as a substitutefor pitch, which is normally used on the back of asheet of metal before repousse work. The partsbrought into relief are worked from the back of thesilver with hammers and modelling punches as thefront is supported with a thick wax pad. The partsthat are concave or depressed are worked from the

Fig. 14. Residues of beeswax on the back of inner plate C 6573,seen as dark scattered areas in the wheel. Photo: E. Benner Larsen.

front with the use of different punches while the backis supported with wax (Untracht 1975, 93 &105; Wil-son 1978, 44; Theophilus 1979, 97ff).

The presence of fine-grained sand, and the re-corded impressions of such sand on the silver, is mostinteresting. Probably it has to do with the chasingwhere it was used as temper in the beeswax on theback of the sheets. Macro-photographs from the backof the plates under discussion very clearly show im-pressions of fine sand grains in the surface of the sil-ver. These impressions are restricted to areas chasedfrom the front of the plate towards its back, on towhich the beeswax pad, tempered with sand, wasmounted. Thus, the sand impressions record the fin-ishing process of the repousse work. It should benoted that such sand impressions in large numbersoccur on the back of the Bull plate, Fig. 15.

Quite different impressions can be seen on thebacks of the outer plates C 6565, C 6566, C 6568,C 6569 and C 6570, in that distinct impressions ofplants have been recorded, which are as clear assharp photographs. These impressions, which arecaused by corrosion, have so far not been botanicallyidentified, but when this has been done they may helpto identify the vegetation in the bog when the caul-dron was deposited.

THE SKETCHPAD OF A MASTER

Most astonishing, and as a precious gift from the past,the close examination of the backs of the silver plates


Fig. 15. Impressions of fine grained sand are clearly seen as smallblack dots of different shape and size on this photograph from theback of the back leg on the Bull plate C 6563. The sand im-pressions are restricted to areas chased from the front of the Bullplate and only in areas where the C-punch has been used, see Fig.4 Toolset III punch O. The width of the photograph represents 16

mm. Photo: E. Benner Larsen.

has revealed the presence of six drawings, which havebeen completely overlooked for more than a century.Admittedly, we have to do with small drawings whichhave been drawn lightly into the backs of the silverplates with a scriber and which are almost invisible tothe naked eye. Some of these newfound drawingsmight be characterized as preliminary sketches. Theyare not simply graffiti, but may have served as anelement in discussions going on between two or moresilversmiths during the making of the ornament; if so,the backs of the plates were used as a sketchpad.

The finest of these drawings was found on in thelower right corner onthe back of the inner plate C6572. It is a male figure, 4.4 cm high, seen in profileand blowing a horn instrument (see Fig. 16). It isworth noting that this instrument looks quite differentfrom the relatively much longer instruments playedby the three carnyx blowers depicted on the front ofinner plate C 6574. On the back of the inner plate C

6573, three drawings have been recorded: a malehead in profile near the right side at the middle (Fig.17 left), much like the horn player mentioned andperhaps the work of the same artist, and the head oftwo cats, likewise in profile, one of which was foundover the male head near the upper corner (Fig. 17right). Corrections in the drawings of the latter crea-tures suggest that they were once the theme of a dis-cussion of the anatomy of cats. Further, these cats aredepicted in a way, which could be characterized as‘naturalistic’. Not a style one would generally associ-ate with the imagery of the Gundestrup cauldron al-though it could be said to be found in the rolling ordead dog (Fig. 6, 5).

Finally, two new drawings have been found on thefront of the inner plate C 6575, but these have an-other purpose than the drawings above in that theymust be considered drafts of motifs agreed and to beexecuted. That is, they were intended as a first stepwithin the repousse technique previous to the contourlines, which were made by tracers. However, contraryto all other similar drawings on the front of the vari-ous plates, these two were never carried out in re-pousse but were left as testimony of a motif which

Fig. 16. I shall never forget the morning when I was studying theback of the inner plate C 6572. I was using a fibre illuminationunit as a light source in an angle over the silver surface when asmall horn blower gradually grew out of the silver sheet. The hornblower seen in profile is 44 mm high and is drawn upside downwith a sharp scriber in one corner of the silver sheet. When he wasfirst drawn, the scratched line, with the metal thrown up alongsideit would have caught the light brilliantly but he is now almostinvisible to the naked eye and was not easy to document. He hadbeen hiding for so long but a combination of silicone rubbermoulds, epoxy resin replicas, macro photography and digital im-aging brought him back to the light. His horn is end-blown andheld in a horizontal position in his right hand. To judge from thedrawing the horn might be a combination of an animal horn onto which a beautifully shaped metal bell has been attached. Thespeaking end has been drawn twice – one under the other. It looksas if the horn has been drawn first and then the man was addedafterwards. The fact that the bell at the outer end was drawn twicesuggests that the drawing may have served as an important elementin a discussion going on among two or more silversmiths about theshape and construction of a specific kind of a musical instrumentin a corner of the workshop while making the Gundestrup caul-dron. Thus the back of the silver sheet served as a sketchpad twothousand years ago. Photo: E. Benner Larsen. Digital imaging: Jan-

nik Weylandt.



Fig. 17. To the left a sketch of a small head and back seen in profile is one of two found on the back of the inner plate C 6573. In style it isvery much like the horn blower, see Fig. 16. The peculiar shape and position of the eye is like the eye of the horn blower, and so are thenose and the hair. The same hand that drew the horn blower probably drew this sketch. – To the right a small sketch of a cat seen in profilewas also found on the back of the inner plate C 6573. The cat is drawn with a scriber on the surface of the silver. The width of the

photographs represents 13 mm. Photo: E. Benner Larsen. Digital imaging: Jannik Weylandt.

was abandoned as the work went on. It is remarkablethat all the three plates with drawings are inner plates,which belong to Toolset II.

CONCLUDING REMARKS

Finally, it should be noted that much work remainsto be done to show how the Gundestrup cauldronwas made step by step. The point of departure willpartly be the results of the scientific analyses, partly acomprehensive study of the details of the cauldron’scraftsmanship, including identification and docu-mentation of the various tools employed. This re-search will be supported by a new photographic docu-mentation of microscopic detail, and not least the em-ployment of silicone rubber moulds, as well aselectroform replicas of all the individual parts of thecauldron. Using these facilities for documentation inthree dimensions, we can expect much new infor-mation about the production of the Gundestrup caul-dron.

ACKNOWLEDGEMENTS

I wish to thank the authorities at the National Mu-seum at Copenhagen for permission to take metalsamples and silicone rubber moulds from selectedareas of the Gundestrup cauldron. I owe the Englisharchaeologist Richard D. Savage and his colleagues,the silversmith Philip Lowery and the conservatorPeter T.H. Shorer cordial thanks for their neverwavering interest and rewarding discussion along thework. Special thanks go to the jewellery historian JackOgden, Heidelberg, as well as the corpus silversmithClaus Bjerring, Copenhagen. Also thanks to ThomasPoulsen and Violette Burka, both employees at thesilversmith’s workshop of Georg Jensen Silver in Cop-enhagen. Discussions with these experts at the De-partment of Conservation at the National Museum,with the Gundestrup cauldron at hand, have beenvery rewarding. Also thanks to conservators ClausGootlieb, Peter Henrichsen and geologist UlrichSchnell, all from the Department of Conservation atthe National Museum in Copenhagen.


Fig. 18. Measurements of the thickness of the bowl, C 6562.

THICKNESS OF THE SILVER PARTSE. Benner Larsen and the present authors did themeasurements of thickness using a Digital ThicknessGauge. At each spot of measurement three readingswere taken and their average value used in the follow-ing calculations. In all 2886 readings were made onthe 16 silver parts of the cauldron and for each partone overall value of thickness has been ranked intoone of groups aΩ0.45–0.55 mm, bΩ0.60–0.65 mm,cΩ0.66–0.70 mm and dΩc. 0.80 mm.

THE BOWL

Readings were made across the outside of the bowl,C 6562, in lines of 40 cm length from the edge to-wards the centre at 3, 6, 9 and 12 o’clock positionsfor each cm, and an average value of each of thesefour sets of measurements was calculated as can beseen from Fig. 18. The average thickness of thebowl can be estimated to c. 0.65 mm (group c). Thebowl distinguishes itself by having four zones aroundit of remarkable even thickness. The bottom is dis-turbed by an irregular hole, but the readings showstabilization to c. 0.70 mm in thickness 40–37 cmfrom the rim. Here the first zone starts as a stable

band with a thickness of c. 0.70 mm that runs up to32 cm from the rim. After this the second zoneshows an even thinning of the silver down to 0.53mm at 27 cm followed by a thickening up to c. 0.65mm at 18 cm from the rim. This remarkable eventhin band around the bowl must partly be due tothe smithing technique used for raising the silver.The third zone consists of a broad stable band be-tween 18 and 4 cm from the rim with an eventhickness of c. 0.65 mm. The fourth and last zoneflattens towards the edge of the rim down to a thick-ness of c. 0.34 mm. All in all the even and sym-metrical structure of the bowl proves it to be an im-pressive masterpiece of silver smithing that would bevery difficult to replicate today.

THE TUBES

Measurements were taken for each cm lengthwise onthe two pieces of tubing from the rim, C 6576 A &B, except for some places where the slit in the bottomof each tube was too narrow for the feeler of thegauge to pass through. The readings indicate that thetubes were made from plates having an approximatethickness of c. 0.8 mm (group d), though they are flat-


Fig. 19. Horizontal measurements of the thickness of outer plate C 6565. The actual width of the plate is 25 cm, but the readings go to 30cm because of the embossed motifs. The left edge is drawn and upset and the right edge is upset to a thickness larger than the original.

tening to 0.4–0.5 mm on the ends. In addition, meas-urements were taken per 0.5 cm around the tubes 2.5cm from their ends. They show a thickness of c. 0.7mm decreasing to 0.4–0.2 mm at the edges of theslits.

THE RECTANGULAR PLATES

On each outer and inner plate thickness was meas-ured with a spacing of 1 cm along a vertical and ahorizontal centred line, except where holes or sharpcurves made it impossible to get a reliable reading.The thickness showed a considerable variation bothwithin each plate and among the individual plates. Asexpected, the silver was much thinner or thicker inthe heavily worked areas (0.19–0.90 mm) than in themore or less undecorated ‘background’ areas (0.45–0.70 mm). Readings of lesser or larger thickness mightbe due to the fact that they were taken in areas wherethere has been a drawing or upsetting of the metal,e.g. between punch marks.

Measurements from undecorated areas gave an im-pression of the original thickness of the plates, and itwas seen that most of the plates before chasing hadbeen somewhat thicker in the middle and thinner atthe edges. This indicates that the plates were drawnboth horizontal and vertical to their final shape by

hammering. The edge itself has often been straighten-ed and upset by hammering though, so it has becomethicker than the metal right inside or even thickerthan the original thickness of the plate (Figs. 19 & 20).

One interesting thing about the original thicknessof the plates is that there is a grouping of the platesthat were decorated by different toolsets (Larsen1985, 571). Plates worked up by Toolset II seem tobe a little thinner (0.45–0.55 mm, group a) than platesworked up by Toolset I (0.60–0.65 mm, group b) ex-cept C 6574 having a thickness of c. 0.50 mm (groupa), which will be dealt with in the section ‘Flow of rawmaterials’. A more pronounced difference, however,exists as to the two plates not belonging to these tool-sets, C 6569 & C 6570. These plates both have alarger thickness of 0.65–0.70 mm (group c).

Table 4 summarizes the measured values accordingto toolsets of the estimated original, the minimum andmaximum thickness together with the thickness of theedges of each rectangular plate. Further, entries havebeen done regarding as to which of five categories the48 values of the edges belong having either beendrawn and/or upset to a thickness lesser, within orlarger than the original thickness. This categoricalgrouping was done by comparing the estimated orig-inal thickness with the thickness of the edge and themeasured values 1–2 cm inside the edge.


Fig. 20. Vertical measurements of the thickness of outer plate C 6565. The height of the plate is actually 21 cm, but the readings go to 25cm because of the embossed motifs. The top and bottom edges are both drawn to a thickness lesser than the original.

Table 4. Measured values of thickness in mm of the rectangular plates according to toolsets together with the thickness of the edges of eachplate and whether the edges are drawn and/or upset to a thickness lesser, within or larger than the original thickness.


The first and largest group of 25 edges have allbeen drawn to a thickness lesser than the estimatedoriginal thickness of the plate and eight of these edgesare also upset. The bottom edge of inner plate C 6574shows the lowest reading of all at 0.16 mm. Mostdominant in this group are the outer plates C 6569and C 6570 with 7 of their 8 edges, while 11 of the16 edges worked up by Toolset I and only half of theedges worked up by Toolset II belong here too.

The second group consists only of five edges thathave been both drawn and upset within the originalthickness of the plate. They are all found on threeplates worked up by Toolset II.

As for the last of the three groups, consisting of 18edges with a thickness larger than the original thick-ness, all have either been upset or both drawn andupset, nine of each. Here the outer plates stand outwith 15 edges, especially six ones being only upset onplates decorated by Toolset II and of these plate C6566 on all four edges. On outer plate C 6565 decor-ated by Toolset I, the right side has the largest readingof all at 0.89 mm. Also one edge on C 6570 belongsto this group, while the last three are found on innerplates decorated by Toolset II. Further, it is evidentthat 14 of the 18 edges in this group are left or rightedges while only four are top or bottom edges.

To conclude, the five inner plates together with thetwo outer plates with no punch marks are dominatedby edges of group one, while the outer plates decor-ated by Toolsets I and II are dominated by the thirdgroup of edges. Also the plates decorated by ToolsetI seem to be worked more down than the relativethicker edges of the plates decorated by Toolset II.

THE BULL PLATE

As for the circular Bull plate (C 6563) worked up byToolset III, measurements were taken with a spacingof 1 cm along the diameter together with measure-ments at 58 selected spots. The Bull plate is thickerthan the rest of the plates with an estimated originalthickness of c. 0.8 mm (group d). The embossed andchased motifs have a thickness ranging from 0.31 mmto 0.94 mm deriving from the working on the plateas explained above. This also applies to the skilfullyworked raised head of the bull (0.33–0.60 mm). Thethickened bead along the edge of the plate has a

thickness of 1.9–2.0 mm. Right inside this, a uniformthinning has been done in a c. 1.5 cm broad zone allaround the plate where the thickness decreases to c.

0.4 mm. This could imply that the metal for the beadwas drawn from this area. As a consequence of thisthinning the bead appear heavier since it is raised c.

1.5 mm above the adjacent surface, even if it is justc. 1 mm thicker than the plate itself.

CONCLUSION

All the parts of the cauldron show in one way or an-other that they have been drawn and/or upset to gettheir final shape. It seems that the plates worked upby Toolset II had an original thickness of 0.45–0.55mm (group a), whereas the plates worked up by Tool-set I had a thickness of 0.60–0.65 mm (group b), ex-cept C 6574 with a thickness of 0.50 mm (group a).The two plates with no punch marks were the thickestof the rectangular plates, 0.65–0.70 mm (group c),and likewise the bowl shows a thickness of c. 0.65 mmthough it is worked up in another way, while the twotubes and the Bull plate show an original thickness of0.8 mm (group d).

METALLURGICAL EXAMINATIONSSmall samples of silver, gilding and tin from the Gun-destrup cauldron have been investigated. Thesamples were embedded in epoxy resin, grinded andpolished. The transverse sections of the chips werestudied by optical and electron microscopy. Themetal analyses were carried out employing scanningelectron microscopy (SEM) in combination with awavelength dispersive spectrometer (EDS).

COPPER CONTENT OF THE SILVER

Small samples (2–4 mg) were taken from the edge ofeach of the 16 silver parts of the cauldron, plus oneextra from plate C 6565 and two more from the bowl,C 6562, 19 samples in all. The metal analyses showthe silver to be relatively pure (87.48–97.15%). Table5 summarizes the contents of metals present withinthe limits of detection (∂0.1%).

All silver parts contained copper. As is normallythe case in hardened melts, the copper was present as


inclusions in the silver. The inclusions were flatteneddue to heavy deformation by smithing and chasing ofthe plates. It could be seen that copper inclusionswere not present in an approximately 100 mm broadzone at the surfaces of the plates. This must be dueto a depletion of copper caused by successive heatingand pickling of the plates during forming. To avoiderroneous results due to surface depletion, analyseswere made in the centre of the transverse sections.

The copper and tin contents of each part are plot-ted against each other in Fig. 21. However, the tincontent should be read with some caution as the sol-der can have contaminated it, but anyhow, the pur-pose of the diagram is to show the copper content.From Fig. 21 as well as Table 5 it is seen that thesilver parts can be ranked into four groups accordingto their copper content and that this grouping almostcorresponds to the grouping according to toolsets asregards the decorated plates.

The parts from the first analytical group ‘A’ aremade of rather pure silver with a low copper contentbetween 1.4% and 2.1%. This group consists of fiveout of the six plates worked up by Toolset II (C 6564,C 6566, C 6572, C 6573 & C 6575), together withthe Bull plate (C 6563) decorated by Toolset III, andone of the four plates decorated by Toolset I, C6567 – the symbol of which in Fig. 21 is partly hiddenby the symbol of C 6575. Group ‘B’, with a mediumcopper content of 3.1–5.2%, consists of the otherthree plates decorated by Toolset I (C 6565 – twosamples, C 6571 & C 6574) and the last plate decor-ated by Toolset I (C 6568), together with the threesamples from the bowl, C 6562. The third group ‘C’has a larger copper content of 6.3–6.4% and consistsof the decorated outer plate C 6570 with no punchmarks together with the rim tube C 6576 B. Thecompanions to these latter parts, rim tube C 6576 Aand the decorated outer plate C 6569 with no punchmarks, comprises the fourth and last group ‘D’ withthe largest copper content of all, 7.8–8.2%.

One might expect the alloy of each part to be uni-form so that several samples taken from the same partwould show nearly the same copper content. Con-sidering the difference between the values of the twosamples from C 6565 of 0.35% and the similar oneof 0.68% between the lowest and highest values ofthe three samples from C 6562, it can be concluded

that their alloys at least show a divergence in the dis-tribution of copper content of c. ∫5% and 7%. Thismargin does not, however, disturb the overall pictureof groups A, B, C and D.

Generally, the metallographic analyses seem to bein agreement with the groupings made on basis oftoolmarks on the plates. The plates decorated byToolsets I and II seem to be relatively uniform in sil-ver alloy, respectively, with the two plates C 6567 andC 6568 being the only exceptions as the silver alloyof these plates fall in an opposite group with respectto toolmarks (see Fig. 21). This could indicate that thesilversmiths making the two groups of plates somehowgot two of the plates or ingots mixed up. When com-pared with the measurements of thickness (see theprevious section) it appears that the mixing up hap-pened before the ingots were hammered out, sincethey have the same thickness as the other ones withintheir respective toolsets. This will be further dealt within the section ‘Flow of Raw Materials’.

Table 5. Metal contents in samples from the silver parts of thecauldron. See also Fig. 21.


Fig. 21. The copper and tin contents in the silver samples. The analyses group almost according to the Toolsets I and II.

Fig. 22. Interdependence between the thickness of the gold layers and their contents of copper. The gold on the plates decorated by ToolsetI have a higher copper content and thickness than the gold on the plates decorated by Toolset II. On the plates C 6563 and C 6569 thegilding has apparently been repaired, resulting in a less adherent outer gold layer of greater thickness and larger copper content than the

original gilding.


Fig. 23. A sample of poorly adhering gold foil from the Bull plate,C 6563, consisting of two layers with the inner one folded. SEM-

photo: Arne Jouttijärvi, Heimdal-archaeometry.

GILDING OF THE PLATES

The gilding on six of the seven outer plates and on theBull plate was examined. Of the nine samples threeconsisted of loose gold foil and six of gold adheringto the silver plate. In some places the gold stuck firmlyto the plates, at other places, the gilding was onlyadhering slightly to the silver, and at yet other placesagain, the gold was peeling off. The thickness of thegold layers varies from 0.7–0.1 mm to 0.25–0.30 mm.From the Bull plate C 6563 was taken both a pieceof adherent gold foil and a loose piece with the latterhaving the highest copper content. The sample of ad-hering gold foil from the Bull plate consists of twolayers (Fig. 23) of which the outer layer is the thickest,while a loose piece from C 6566 consists of threelayers with the middle layer being the thickest andthe inner layer having a none traceable copper con-tent but a high silver content. From plate C 6569 wastaken both a piece of adherent gold foil and a loosepiece. The adherent piece consists of nearly puregold, while the loose piece has a higher silver andcopper content. The loose piece can derive from alater repair.

The gold can be sorted into two groups, of whichone consists of pure gold with low contents of silver

Fig. 24. A sample of adhering gold foil from plate C 6569 withsigns of diffusion of silver into the gold. SEM-photo: Arne Jout-

tijärvi, Heimdal-archaeometry.

and copper. To this group belong the samples fromplates C 6564, C 6566 and C 6568 decorated byToolset II. The other group has a higher content ofsilver and copper. Plates C 6565 and C 6567 of Tool-set I belong to this group. Fig. 22 shows that the thick-ness of the gold is correlated to its pureness. Thepurer the gold is, the thinner the foil.

The adherence of the gold to the silver generallyseems to be quite poor, cf. Fig. 23. The silver contentsof the gold foils may be due to diffusion from theunderlying silver (diffusion bonding), see Fig. 24.None of the gold analyses showed any sign of mer-cury. Thus, fire-gilding technique was not used on theGundestrup cauldron. The overall impression is thatgilding was not made by deliberate diffusion bonding,but primarily by mechanical means. The closelyspaced punch marks in many of the gilded areascould have served to fix the gold to the silver surface.

TIN

A total of five tin samples were analysed. Three ofthese come from soldering, whereas the remainingtwo come from tin fillings behind the eyes of the facesof the outer plates (Fig. 25). In all cases, the tin is very


Fig. 25. Tin fillings behind the glass eyes of plate C 6567. Photo:E. Benner Larsen.

pure; there is nothing to indicate that we are dealingwith an alloy. As appears from Table 6, the results ofall analyses are very homogeneous, yet with a ten-dency to the tin behind the glass eyes having a lowercontent of silver, copper, and gold. Among these threemetals, only silver is present in an amount allowingsafe identification. Thus, copper and gold make outless than 0.1%, making the analyses very uncertain inthis respect. The variation as to silver content may beexplained as a result of some dissolution of silver fromthe plates. However, the thickness of tin behind theglass eyes is large. Therefore, it is unlikely that dissol-ution of metal from the plates can be recorded here.

LEAD ISOTOPE ANALYSESPb isotopic analyses presented in this study were de-termined using a new technique described in detail(Baker, Stos & Waight in press) and only a brief over-

Table 6. Metal contents in tin samples from the soldering and thefastening of the glass eyes on the cauldron.

view is given here. Samples were prepared by placingsmall fragments of metal (0.5–2.5 mg) sampled usingeither a jeweller’s saw or a small round nose engraverchisel into a pre-cleaned 1.5 ml polypropylene centri-fuge tube. Ten microlitres of concentrated distilled ni-tric acid was then added to the metal chips to bringthem rapidly into solution. One millilitre of 0.2% ni-tric acid was then added to the sample, as well asa small amount of Thallium to allow for mass biascorrection (see below). As these solutions commonlycontained significantly higher concentrations of Pbthan needed for an analysis, the solutions were centri-fuged to remove undissolved solids and then a smallaliquot was removed from the parent solution tocreate a 1:100 dilution. No further dissolution orchemical separation of Pb was performed on thesample as our tests have shown excellent agreementbetween duplicate analyses performed by MC-ICPMS using the above dissolution techniques onsamples chemically processed to concentrate Pb(Baker, Stos & Waight in press).

Analyses were performed on a double focusingmultiple collector inductively coupled plasma massspectrometer (MC-ICPMS housed at the DanishLithosphere Centre, Copenhagen). Analyses areionised in an argon plasma following uptake throughan Aridus desolvating nebuliser. The instrument util-izes an electrostatic analyzer to narrow ion energiesand has one fixed and eight movable Faraday collec-tors allowing static measurement of all isotopes(200Hg, 201Hg, 202Hg, 203Tl, 204HgπPb, 205Tl, 206Pb,207Pb, 208Pb) necessary to measure Pb, account forinstrumental mass bias and isobaric interferencesfrom Hg. More details on instrument set-up and op-erating conditions are given in Baker, Stos & Waight(in press).

Prior to sample uptake, background signals weremeasured on mass for 1 min. in a solution of the exactsame molarity as that which samples are dissolved toaccount for small signals from Hg (present in the Argas) and residual and stable Pb memory (,0.2 milli-volts on mass 208). These Pb backgrounds reflect aresidual memory from previous analyses, yet have aconstant size and composition over periods consider-ably longer than individual analyses and are thereforeeasily accounted for by the on-peak zeroes routine.Following measurement of backgrounds, the sample


solution was aspirated and, once a steady signal wasattained, data collection began. Data were acquiredas 100¿1 s. measurements and baseline values weresubsequently subtracted from raw count rates, andany variations in Hg signal size during the analysiswere accounted for by using measured signals oneither 200Hg, 201Hg or 202Hg to correct for the iso-baric interferences of 204Hg on 204Pb. The three dif-ferent Hg isotopes are monitored to monitor possibleerroneous isobaric interference corrections due toother isobaric interferences on masses 200–202.

Using MC-ICPMS it is possible to more accuratelyaccount for mass bias due to the similar ionization ofelements of similar mass in the Ar plasma. The ratioof 205Tl/203Tl added to the sample is measured simul-taneously with the Pb isotopes and the divergence ofthis ratio from a natural ratio of 2.3889 yields a massfractionation factor that is subsequently used to cor-rect for mass bias on the measured Pb isotopic ratiosusing the exponential mass fractionation law. Typicalmass bias for the instrument is 0.8–1.0% per a.m.u.Replicate analyses (nΩ13) of the SRM981 standardyielded values of 206Pb/204PbΩ16.948∫9, 207Pb/204PbΩ15.508∫11, 208Pb/204PbΩ36.751∫37, 207Pb/206PbΩ0.91502∫21, 208Pb/206PbΩ2.1686∫11 (2 s.d.)which are in good agreement with previous studies(Baker, Stos & Waight in press). The results of thelead isotope analyses of 34 samples from the Gun-destrup cauldron are shown in Table 7 in the nextsection.

LEAD ISOTOPE PROVENANCE STUDIESTHE METHODOLOGY OF LEAD ISOTOPEPROVENANCE STUDIES OF ANCIENT RAW MATERIALS

Since the last quarter of the previous century leadisotope provenance studies have been often success-fully applied in research concerned with identificationof sources of raw materials used in Antiquity, in factcopper and lead-silver (Gale and Stos-Gale 2000).The principle of this technique is based on isotopegeology, providing scientific evidence of the variedlead isotope compositions of terrestrial rocks and min-erals. Due to factors related to the formation of theEarth and subsequent chemistry of formation of min-erals, in principle, each mineral deposit on Earthhave a distinctively different pattern of lead isotope

compositions. In turn, all ancient materials madefrom minerals, including metals and pigments, willhave lead isotope compositions identical with theminerals from the copper and lead-silver mines theycome from.

The variations of lead isotope abundances in allore deposits are in the first instance related to theperiod of formation of the mineralisation. This re-lationship is, however, not the only factor decidingthe lead isotope compositions of minerals from vari-ous ore deposits. Therefore, it is not possible to pre-dict accurately enough for the provenance studies thelead isotope ratios of lead in various ancient mines.For comparisons of lead isotope ratios of ancientartefacts with those of minerals it is necessary to ac-cumulate an extensive database of lead isotope com-positions of ore deposits that have been, or mighthave been, exploited in various periods of the past.Additional information necessary for the evaluationof lead isotope data is the chronology of exploitationof the ore deposits and evaluation of the smelting sitesassociated with the mines.

During the past 20 years there have been severalresearch programmes in the UK and Germany inparticular, where a survey of ancient mining districtsand reconstruction of the history of their exploitationwas combined with lead isotope characterisation ofthe ores (see for example: Stos-Gale et al. 1998; Wagn-er et al. 1986 and 1989). Systematic analytical workin the Isotrace Laboratory at Oxford during that timecontributed several thousands lead isotope samples ofores from ancient European copper, lead and silvermines. The majority of these have been published inArchaeometry in the years 1995–1998. Many lead iso-tope samples have been also published in geologicalpublications relating to geochronological studies ofvarious ore deposits. These data can also be used forprovenance studies.

All the lead isotope data mentioned here for com-parisons with the Gundustrup cauldron samples, havebeen obtained using Thermal Ionisation Mass Spec-trometry (TIMS), a technique that is very accurate(overall error of analysis for each lead isotope ratio is∫0.1%) and fully comparable and reproducible be-tween the TIMS laboratories. With due care, all leadisotope analyses performed on the MC-ICPMS arealso fully comparable with TIMS data.


Table 7. Lead isotope analyses of silver parts of the Gundestrup cauldron sorted according to batch of silver and the relationship between207Pb and 206Pb.


SILVER ORE DEPOSITS: POSSIBLE SOURCES OF

SILVER FOR THE GUNDESTRUP CAULDRON

Silver has been a highly valued metal in Europe andthe Near and Middle East since the 4th millenniumBC. In contrast with gold, silver was not mined orcollected as metal in its native state, but has beenextracted from lead-silver bearing ores by the processof cupellation since at least the 3rd millennium BC(Gale and Stos-Gale 1981a & b; Stos-Gale and Gale1980, and 1982). Amongst ancient Egyptian artefactsare also white metal containing varied amounts of sil-ver and gold, from over 90% to less than 50% ofsilver, indicating that some of the native metallic al-luvial gold used in Egypt contained very high concen-trations of silver (Gale and Stos-Gale 1981c). How-ever, in the first millennium BC the process of cemen-tation, that is separation of silver from gold started tobe applied in the Near East and the great majority ofancient silver from the Old World contains gold onlyin quantities below 1% plus any amount of copper,that was deliberately added to the alloy.

The elemental analyses of the Gundestrup caul-dron plates provided by Jouttijärvi show compositionstypical of silver obtained through cupellation of lead/silver ores with some copper added. The gold contentis typical of unrefined silver used for Greek coins andArabic dirhems alike (see for example: Gale et al.1980; Stos et al. 1977). The tin content is higher inthe samples taken from C 6569 and C 6570 thanwould be expected (0.7% and 1% respectively), butthat might be rather due to the contamination fromthe solder, rather than, for example, from usingbronze for alloying (rather than copper), becausethere is no correlation between copper and tin con-tents in the plates. The lead content is quite withinthe range of concentrations expected from cupelledsilver (0.1–0.7%). Copper metal extracted from thecopper ores in the Antiquity rarely contained morethan 1–2% lead. Since all plates of the cauldron con-tain less than 10% copper, lead originating from thecopper in this alloy would contribute only a verysmall fraction to the lead in the silver. In a case of1% lead in the silver and 1% lead in the copper, thealloy would contain nearly ten times more lead fromthe silver than from the copper, so the lead isotopecomposition of the alloy would be basically the sameas that of lead in silver.

Due to the high market value of silver, the silver de-posits in the Old World have been well known and ex-ploited more or less continuously since the Bronze Age.In the Middle East the most important silver depositsare in central and northern Iran (Bariand et al. 1965).In Turkey the principal silver mines are in the TaurusMountains and in the North-West (Yener 1986; Ryan1960). Some silver can be found in the RhodopeMountains on both Greek and Bulgarian sides. InGreece are also the famous mines in Laurion in Attikaand in the Chalkidiki peninsula. In Central Europe themajor silver deposits are in the Bohemian Massif, in-cluding Erzgebirge (Czech Republic and Saxony), inthe Harz Mountains, and in the Eastern Alps (southernAustria and eastern Switzerland). In France, silver wasmined in Britanny and in the Massif Central. In pres-ent day Italy, the major silver deposits are on the islandof Sardinia. Spain was famous for its silver in the Ro-man period (the Rio Tinto mines in the southwest andmines on the north coast of the Iberian Peninsula). Thelarge lead deposits of the British Isles also yielded somesilver but this metal was never of major importancethere. Silver mining has never been of much import-ance in Scandinavia either (Dunning et al. 1986).

The lead isotope characterisation of the silver de-posits of the Old World is not by all means complete,but there are at least a few sets of data for most ofthe major silver mining regions. The Oxford IsotraceLaboratory Lead Isotope Database (OXALID) alsocontains several hundreds analyses of Mediterraneansilver artefacts from 3rd–1st millennium BC, includ-ing Bronze Age artefacts, Greek coinage and Hacksilb-

er from the Near Eastern hoards. We have also ana-lysed over 100 samples of Sassanian silverware datedto 3rd–7th century AD, sampled by Meyers (Harperand Meyers 1978). These two large groups of ancientartefacts give a good idea of the lead isotope charac-teristics of silver used in the Eastern Mediterraneanand the Middle East. For the Western Mediterraneanthere is a good database of ores from Sardinia andSpain (Stos-Gale et al. 1995); additionally, OXALIDcontains data measured on nearly 100 samples fromPhoenician silver production sites in S-W Spain (un-published data, analyst B. Rohl, samples from Uni-versity College London).

Central European silver is far less well character-ised. There are some data for the ores in the Bohem-


Fig. 26. Lead isotope ratios of Eastern Mediterranean silver ores and silver hoards, and the Gundestrup cauldron.


Fig. 27. Lead isotope ratios of Sassanian silver and Iranian ores, Celtic silver coins and the Gundestrup cauldron.


ian Massif (Czech Republic and Saxony), the Erzge-birge, the Harz Mountains, western Germany, Aus-tria (Eastern Alps), and France, but these analyseshave been mostly carried out for the purpose of geo-chronological studies of the ore formations and thereare no particular emphases on the ancient silver min-es. Therefore, it is only possible to assess the generalrange and trends of the lead isotope characteristics ofthe latter. It is not possible to know exactly the group-ings of lead isotope ratios for each mine. Lead isotopeanalyses of ancient silver artefacts from Central andnorthern Europe are very scarce.

LEAD ISOTOPE COMPOSITIONS OF THE GUNDESTRUP

CAULDRON AND THE ORIGIN OF ITS SILVER

The samples of the Gundestrup Caldron have beenanalysed in the Danish Lithosphere Centre Labora-tory using a new generation mass spectrometer calledMulticollector Inductively Coupled Plasma MassSpectrometer (MC-ICPMS), as explained in the pre-vious section by Drs. J. Baker and T. Waight. Theinstruments of this type are capable of much moreaccurate measurements than TIMS and the pro-cedure is much simpler. It has been confirmed thatthe data is fully comparable with the TIMS analyses.

The lead isotope ratios measured for the cauldronare listed in Table 7. The lead isotope data can bepresented as x, y, z parameters of points in three-di-mensional space using the ratios xΩ207Pb/206Pb, yΩ208Pb/206Pb and zΩ206Pb/204Pb. For metal madefrom ores of a given ore deposit the x, y, z parametersfor at least one sample of ore from the deposit andthe metal artefact should be identical within the rangeof analytical error. Comparisons of large numbers ofdata are made using a simple software calculating Eu-clidean distances between the data-points. A visualcomparison between a limited number of samples canbe presented using two mirror diagrams of the projec-tions of the data points on the x-y and x-z planes.

The Euclidean distance from each of the lead iso-tope data points obtained for the silver samples of theGundestrup cauldron has been calculated for some3,000 lead isotope ratios of ores from Europe and theNear and Middle East. The lead isotope character-istics of the silver used for the cauldron are distinctlydifferent from all Eastern Mediterranean, Anatolian,

British, and Scandinavian silver ores. They are alsoquite different from the great majority of the westernMediterranean and Central European silver ores.

Fig. 26 is a mirror diagram of lead isotope ratiosof a large group of silver artefacts from the EasternMediterranean dated to 3rd–1st millennium BC com-pared with groups of known silver ores from Turkeyand Greece. As could be expected, the lead isotoperatios of artefacts are broadly identical to the silverores in this region. Not all deposits were exploited ineach different period, but the picture of silver fromthis region is also valid if silver hoards were re-meltedand re-used. Lead isotope compositions of newbatches of silver obtained from melting, say, silverfrom Laurion (Attica) and Northern Greece, or, Lau-rion and the Taurus Mountains, would lie along thehypothetical ‘isotopic mixing lines’ drawn on thefigure.

The plot in Fig. 26 also includes all data pointsfor the Gundestrup cauldron. The analytical error forthese data is much smaller than the TIMS overallerror of 0.1%. Therefore, it is quite reasonable to as-sume that the differences in isotopic compositions ofdifferent plates are real, resulting in a spread of thedata for the cauldron about 0.5% for all three ratios.The comparison presented on Fig. 26 shows clearlythat the lead isotope data for the Gundestrup caul-dron samples are not identical with any of the EastMediterranean ores and silver artefacts. Neither dothey fall on any of the ‘isotopic mixing lines’. In par-ticular, all the y values (208Pb/206Pb) for the cauldronsamples are higher than measured for the silver oresin any of the Eastern Mediterranean ore deposits.

This visual comparison clearly shows that theplates of the cauldron are not made of silver from onesmelted (or melted) batch. All the data elements forma relatively compact group, the x range (207Pb/206Pb)being less than 0.6%. This might reflect a range oflead isotope compositions from one ore deposit, asdemonstrated on Fig. 26 by the ores from Laurion.However, these data points could also represent silverfrom more than one mine, or silver produced by re-melting silver metal of more varied isotopic compo-sition in small in small quantities, batch by batch.

From all silver-related lead isotope data on theOXALID database the closest comparisons for theGundestrup cauldron are amongst some of the objects


of Sasanian silver and the Celtic coinage from Franceand Germany. On Fig. 27 these two groups ofartefacts are compared with the data for the plates ofthe cauldron.

While some of the plates seem to be isotopicallyvery similar to some of the Sassanian silver, it is clearfrom this plot that the general line of distribution ofdata of the eastern artefacts is not the same as theline of lead isotope ratios of the plates of the cauldron.The cauldron plates, fall between two groups of Celticsilver coins: the quinars of the Oppida of Dünsburgand Heideränktal on the banks of the Rhine near theTaunus Mountains (Zwicker et al. 1989), and the Co-riosolite coins (1st Century B.B.) from Brittany (Grueland Gale 1981). The few lead isotope data for someof the Iranian lead/silver ores fall temptingly close tothe Celtic coins. However, it is nearly certain that thelarge portion of Sassanian silver was made of silverfrom Iranian mines (and, especially, Afghan), andthere are many more analyses of this metal than ofthe ores. We have to wait for much more comprehen-sive lead isotope studies of the silver ores from Iranand Afghanistan, combined with evidence of thechronology of their exploitation. For the moment, itis nearly certain that the isotopic similarities betweenthe Iranian ores and the west European Celtic silverare deceptive.

On the other hand, there are lead isotope analysesof some silver ores from the Eastern Alps (Austria),which are identical with some of the cauldron platesand the Celtic coins. Their data are plotted on Fig.28. For comparison, also plotted, are data from thelargely Phoenician silver smelting debris (litharge andore samples) of Monte Romero and Rio Tinto inSpain. Notably, these data do not conform with thegroup of cauldron Plates, nor with the Celtic coins.

In conclusion, therefore, it seems that the mostprobable origin of the silver used for the manufactureof the cauldron was from the ‘pool’ of silver used inCeltic northern France and western Germany.

LEAD ISOTOPES AND THE PROCESS OF

MANUFACTURE OF THE CAULDRON

Different plates of the cauldron have been identifiedby their toolmarks and art-historical features as beingproduced by three or more artists (Larsen 1985). On

Fig. 29, the lead isotope data for the cauldron platesare plotted according to the identified toolsets, seeFig. 4 for reference.

Each of the plates have been sampled in at leasttwo spots; the lead isotope data for two samples fromthe same plate are in nearly all cases identical within0.02% of the ratio of each. The identical results formultiple samples from all plates of the cauldron showthat the MC-ICPMS analyses of lead isotope ratios ofthis silver are highly accurate. It therefore seems poss-ible to suggest that the isotopic differences betweenthe plates represent real differences between thebatches of silver.

For lack of lead isotope data from one ore depositthat would span the whole range of lead isotope com-positions measured on the cauldron, it can be sug-gested that the silver for making the plates was pre-pared by re-melting ingots or scrap silver (or both) inquantities sufficient for making several plates fromone batch. This hypothesis does not preclude thepossibility that somewhere is a silver mine with thisparticular range of lead isotope composition. How-ever, at present, the hypothesis of the silver used forthe cauldron being re-cycled metal seems more prob-able. It also seems most likely that most, if not all ofthe plates, including the bowl, the bull plate, and therim, have been made in the same workshop and atthe same time. The overall range of lead isotope ra-tios and their alignment seem to imply that silverfrom only two sources, melted together in somewhatdifferent proportions, was used. Further evidence sup-porting this hypothesis is in the fact that differentplates made by the same artist originate from differentbatches of alloy.

The assumption is that the first batch of moltedsilver mostly contained material from the same sourceas the one used for the quinars, namely from the silverrich Taunus Mountains. The next batches mostly in-cluded the same silver as used in northern France forthe Coriosolite coins. If so, the resulting lead isotopecompositions of the cauldron plates would be just asseen on Fig. 29.

The first batch of silver was used for making plate C6570, with no punch marks. The bowl (C 6562) andthe two tubes from the rim (C 6576 A & B) weremade from the same sheet of silver of very similarisotopic composition (and therefore origin). Further,


Fig. 28. Lead isotope ratios of Sassanian silver, Celtic silver coins, silver ores from Central Europe and Spain, and the Gundestrup cauldron.


Fig. 29. Lead isotope ratios of the plates of the Gundestrup cauldron and Celtic silver coins.


C 6572 (Toolset II), C 6565, C 6571 and C 6574 (allthree Toolset I) were made of the same silver.

The Bull Plate (Toolset III) stands separate fromthis group and might have been made from a cruciblemelt, the second batch. One way of making this platewould be to melt a small amount of scrap silver in acrucible, after which the silver collected at the bottomwas hammered on a mould with the bull pattern.

The third batch of silver was used to make C 6566,C 6573 and 6568 (all Toolset II).

The fourth batch of silver was used to make C 6575(Toolset II) and C 6567 (Toolset I).

The fifth batch of silver was used for C 6569, withno punch marks. The sixth batch of silver was used tomake C 6564 (Toolset II).

This evidence shows that Toolset I used twobatches of silver, while Toolset II relied on fourbatches of silver used in the Celtic Rhinelands andNorthern France. Plate C 6569, with no punchmarks,seems to be from melted silver scrap identical to thematerial used in Northern France for Coriosolitecoins of the 1st Century BC.

LEAD ISOTOPE ANALYSIS OF TIN SAMPLES FROM THE

GUNDESTRUP CAULDRON

Five samples of tin from the cauldron were analysedfor their lead isotope composition by Tod Waight andJoel Baker. The results are given in Table 8. Leadisotope analyses of ancient tin ingots and cassiteritesfrom various locations have been carried out in theIsotrace Laboratory, Oxford, by Noel Gale andRobin Clayton within the framework of the Leverhul-me funded research project into sources of ancienttin. Some of the data have been published in the Pro-

Table 8. Lead isotope analyses of tin samples from the Gundestrupcauldron.

ceedings of the Archaeometry Symposium held in Budap-est in 1999. The results of this work have confirmedthat the lead isotope compositions of tin ores (cassiter-ites) in one deposit are far more varied than in copperand iron mineralisations. Therefore, provenancestudies of tin are far more complicated to carry outand less reliable than those of copper, iron, lead, andsilver.

Nevertheless, comparison of the lead isotope com-positions of the tin from the Gundestrup cauldronwith the data collected by Gale and Clayton on cas-siterites from Erzgebirge, Spain, Cornwall and theAsia show that only amongst the cassiterites fromCornwall there are samples with a lead isotope com-position identical to the Gundestrup samples.

In the OXALID database is found Noel Gale’sanalyses of lead in seven ancient tin ingots found inCornwall (the samples were given to us by the lateRonnie Tylecote). The dates of these ingots are verytentative, but three are described as 3rd–6th centuryAD, two as ‘Prehistoric’, one perhaps medieval, andone Iron Age. As can be seen from Fig. 30, the tinfrom the Gundestrup cauldron plots exactly on themixing line of these ores and ingots, with one sample(C 6566, eye) being identical isotopically with the in-gots from Penwithic (Prehistoric?) and Carnanten (3–4th century AD), and at least one sample of Cas-siterite.

CONCLUSIONS

The interpretation of lead isotope data obtained forthe silver of Gundestrup cauldron presented heredoes not necessary prove that this object is of Celticorigin. Also, lead isotope analyses can never providea scientific date of an object. The interpretation ofthe origin of the silver has to be viewed with cautionat present, being based on very few analyses of Celticsilver coins.

However, it seems like more than a coincidencethat the only lead isotope data, out of a reasonablyextensive database related to ancient silver, fallingwith the silver of the cauldron are the Celtic coinsfrom North-west Europe. This result strongly suggestthat the Gundestrup cauldron has been made of silverthat was circulating in North West continental Eur-ope in the pre-Roman period. The use of Cornish tin


Fig. 30. Comparison of lead isotope compositions of ancient tin ingots found in Cornwall, Cornish tin ores and tin from the Gundestrupcauldron.


Fig. 31. The four preserved glass eyes of the faces on the outerplates. From the top: Both eyes of C 6567, left eye of C 6566 and

right eye of C 6570. Photo: E. Benner Larsen.

in the eye sockets of the figures is quite in keepingwith this hypothesis.

The discussion presented here is the best answer

possible in view of the available evidence. It is likelythat in the future, if and when a much more extensivedatabase of the Central and North-Western Europeansilver became available, these data can be re-exam-ined and re-evaluated.

THE EYES OF THE FACESWhen the cauldron was found, archaeologists sup-posed the four surviving inlays of the eyes of the faceson the outer plates to have been made of dark-col-oured glass (Fig. 31). Only modern analytical tech-niques allow the investigation of these in situ. If, dur-ing examination, the inlays would turn out to bemade of glass and not of precious or semi-preciousstones, it was hoped to gain insight into the prov-enance and technology of the specific glass type, and,possibly also to draw conclusions on the date of thecauldron’s making.

METHOD

X-ray detecting techniques, such as X-ray fluor-escence (XRF) spectrometry or ion beam techniquesprovide an efficient instrument for non-destructive,multi-elemental and sensitive analyses of glass objects.For the cauldron’s examination, a mobile MicroXRFset-up (ArtTAXA, intax Berlin, Germany) wasapplied (Bronk et al. 2001). This spectrometer isequipped with an air-cooled low-power X-ray tubecombined with polycapillary optics to generate ahigh-intensity beam of c. 0.1 mm spot diameter, asilicon drift chamber detector, helium purging andvarious light diodes for positioning and lighting of theobject’s surface. Within acquisition times of about 5to 10 min a characteristic fluorescence spectrum ofelements from sodium to uranium can be measured.

The principle of XRF shall be briefly explained: Aprimary X-ray beam penetrates the sample surface –in siliceous materials to a depth of a few hundredmicrometer maximum – and interacts with the atomsof the various elements. The primary beam causeslosses of inner-shell electrons (i.e., electrons in orbitalsnear the atomic nucleus). The electronic gaps arefilled by transitions of electrons from higher orbitals,and the energy difference is emitted as so-called X-ray fluorescence radiation. This fluorescence radi-


ation has distinct energy values for each element, andits specific intensity in the spectrum is used for quanti-tative calculations of the elemental composition, e.g.by calibration with similar reference standards. Al-though the technique itself does not require taking asample, certain preparation of the measured area isinevitable. First, an organic coating from a past con-servation had to be removed using toluene. Second,polishing with a diamond paste aimed to remove thefirst micrometers of the glass surface, which has analtered composition due to the long burial in the bog,was employed.

RESULTS AND DATA INTERPRETATION

The four inlays (plates C 6566, C 6567 with two in-lays, and C 6570) are all of a round, slightly lens-shaped form; the visible width of the inlays on C 6566and C 6570 is c. 4 mm, see Fig. 31. Under the micro-scope they all appeared to be of a dark purple colour.One piece revealed a small streak of opaque whiteglass, which could be investigated separately.

The analyses confirmed that all inlays are indeedmade of glass, each of a very similar soda-lime typecomposition. As principal elements, the transparentpurple glasses contain, in average, 67% SiO2, 16%Na2O and 8% CaO, with only little variation. Lowpotassium and magnesium contents (below 1% of theoxides) allow to conclude the following on the fluxingmaterial: mineral soda (trona), a mixture of sodiumcarbonates, sulphates and chlorides, which forms asan evaporation product in salt lakes like, e.g., theWadi Natrun in Egypt.

Glasses basically made from calcareous sand andmineral soda are typical for the Mediterranean regionand especially for the glass production in Hellenisticand Roman times. As far as is known today, the use ofmineral soda in the production of vessel glass startedaround 650 BC and continued far into the first mil-lennium AD (Wedepohl 1998, 36ff). Production cen-tres for raw glass of this type were located at the Eastcoast of the Mediterranean (today Israel, Palestineand Syria). Archaeological excavations of Romanglass-melting tanks have brought glass blocks of sev-eral tons’ weight to light, which in an impressive waygives evidence for the high technical level of glassmaking at this time.

It is generally assumed today that raw glass wastraded in lumps over long distances, re-melted andworked into perfume bottles, bowls and drinkingglasses, lamps, window panels, tesserae (cubes for mo-saics), sculptures and enamelled jewellery by crafts-men in other places. In comparison to Hellenistic andRoman style, the range in Celtic glass finds is muchmore limited: only jewellery, such as bracelets andrings, is known (see, e.g., Gebhard 1989). Often trans-parent coloured glass is decorated with trails ofopaque white or yellow glass. Material analyses ofCeltic glass have revealed soda-lime glasses, whichallow us to suggest a production in the Mediterraneanregion.

Not only the fluxing material of the cauldron’sglass, but also the metal oxides for colouring andopacification deserve specific consideration: A highmanganese content of around 1.8% MnO lends theglass eyes their intense purple tint. The earliest findsof such purple glass in Celtic settlements in Germanyand Austria were dated by archaeologists to theMiddle and Late Latene period (LT C2/D1) around125 BC (Gebhard et al. 1989; Karwowski et al. sub-mitted).

The single white streak in one of the inlays con-tains small crystals of a calcium antimonate com-pound (either Ca2Sb2O7 or Ca2Sb2O6), which scat-ter the light and render the glass opaque. Interest-ingly, the white glass contains at least 8% PbO,whereas the lead oxide content of the purple glass isonly between 0.05 and 0.26% PbO. The opac-ification most likely happened during the meltingafter addition of an antimony mineral, such as stibn-ite (Sb2S3), to the batch. The presence of lead is notessential for the formation of calcium antimonatecrystals but may have helped to decrease the work-ing temperature of the glass. A prominent Romanexample with white cameo glass decoration of simi-lar lead-rich composition is the famous Portland cameo

vase (c. 25 BC to 25 AD) now at the British MuseumLondon (Freestone 1990). Such lead-rich opaquewhite glass was also found in Celtic excavationsfrom Austria between 250 and 50 BC (P. Wobraus-chek personal communication 2002). A survey ofnumerous analyses of Roman glass clearly showsthat this type of white glass with high lead contentcompletely disappeared after 100 AD, and was re-


placed by opaque white glass with no or only minorlead addition.

CONCLUSION

To conclude, the analyses of the glass inlays of theGundestrup silver cauldron rather unexpectedlyallowed narrowing down the production time of theglass between the second century BC and the firstcentury AD. However, it should be kept in mind thatthe making of the cauldron may still have been doneafter this period: The small glass eyes could have beencut from a fragment of a vessel, bracelet or any otherused object. The primary glass was produced on thecoast of the Mediterranean and probably re-workedafter having been traded to the north. Finally, the

Table 9. The silver parts of the Gundestrup cauldron grouped ac-cording to toolset, batch of silver, copper content and originalthickness in order to show the anomalies between them. The tableis based on data from Tables 3, 4, 5 and 7.

application of glass onto a silver object of such highvalue and meaning as the Gundestrup cauldronclearly reflects how highly esteemed glass was in An-tiquity.

ACKNOWLEDGEMENTS

The authors would like to thank the colleagues inCopenhagen for making this project possible. We aregrateful to Ian C. Freestone, Rupert Gebhard, MaciejKarwowski, Christoph Jokubionis and Peter Wobrau-schek for fruitful discussions on the data interpreta-tion.

FLOW OF RAW MATERIALSBy comparing the copper content, thickness andweight of each part of the Gundestrup cauldron ac-cording to the batches of silver and the toolsets usedin the process of manufacturing an attempt can bemade to determine the logistics of the workflow fromraw materials to intermediate plates. The relevant re-sults of E. Benner Larsen, A. Jouttijärvi and Z.A. Stosfrom Tables 3, 4, 5 and 7 have been summarized inTable 9 to clarify the connection between their obser-vations, and most of all anomalies of these.

The workflow of the manufacturing process canbriefly be described as follows. The batches of silverwere divided and melted in crucibles with some cop-per added to make the alloy subtler. From these cru-cible melts probably flat ingots were cast and ham-mered out to intermediate plates that could be furtherworked up to the final shape of the parts.

WEIGHT OF THE BATCHES OF SILVER

As Z.A. Stos pointed out in the previous section, sixbatches of silver have been used in the manufacturingof the parts, as determined from Pb-isotope contents.Of these six batches, the first one consists of threesubgroups. Table 9 shows that batches 1, 2, 5 and 6have only been used for one part each, whereas sev-eral parts have been made from each of batches 1a,1b, 3, and 4.

Adding the weight of the individual parts theweight of each batch of silver can be calculated aslisted in Table 10, though the weight of the other


added materials are included in these data too. Theweight of the batches differs considerable from batch1a of 3,963.4 g to the 298.5 g of batch 6, so the cru-cible for melting the alloy to the ingot of 3,736 g forthe bowl, C 6562, must have been rather large com-pared to that for plate C 6569 made of batch 6. Thisspan in volume leads to the question if the batchesused for several parts were melted in one piece ordivided before melting. Looking at the very uniformCu-contents of plates C 6567 and C 6575 made outof batch 4 (1.84% and 1.82%, see Table 5), it seemspossible that their ingots could come from the samecrucible melt, whereas other parts show different Cu-contents in between the same batch. So, the questionremains open whether or not the batches of silverwere divided before their melting.

ANOMALIES IN RELATION TO BATCHES AND COPPER

CONTENT

In A. Jouttijärvi’s section on metallurgy it was con-cluded that the Cu-contents of the ingots for plates C6567 and C 6568 maybe were switched between thework groups of Toolsets I and II, before the plateswere hammered out. Apparently, this is not a simpleproblem, when comparing with the results of Z.A.Stos shown in Table 9, from which it also can be seenthat some of the parts made from batches 1a, 1b and3 show a different Cu-content than other parts madefrom the same batch. Likewise, Z.A. Stos concludedthat parts of batches 1b and 4 have been divided be-tween Toolsets I and II, then, how and why? To cla-rify this matter the following observations have beenmade, and to support this Fig. 32 depicts the Cu-contents against the lead isotope ratio of 207Pb/206Pb.Also, use Fig. 21 for reference.

The three parts made from batch 1a differentiatesfrom each other in having different copper contents.So this batch must have been divided in three beforethe copper was added to each crucible melt. Here thebowl C 6562 shows the same copper content of group‘B’ as the plates worked up from batch 1b by ToolsetI, suggesting that the same work group melted all ofthe alloys used for these parts. The two tubes differen-tiate in C 6576 B having the same Cu-content ofgroup ‘C’ as outer plate C 6570, and the other tubeC 6576 A the same of group ‘D’ as outer plate C

6569. After casting, the ingots were switched two bytwo to be hammered out into the tubes of thickness‘d’ and the outer plates of thickness ‘c’.

The inner plate C 6572 made from batch 1b andworked up by Toolset II has a Cu-content of group‘A’, not ‘B’ as the other three plates made from batch1b worked up by Toolset I (see Table 9, Fig. 21 &Fig. 32). This Cu-content of group ‘A’ is consistentwith four of the other plates worked up by Toolset II.So, a possible explanation to this could be that thework group of Toolset II has received some raw silverof batch 1b from the work group of Toolset I, andhas then added copper to the melt so that the Cu-content became ‘A’ in the ingot hammered out toplate C 6572 of thickness ‘a’, consistent with the restof the plates worked up by Toolset II.

Something different applies to the three platesmade from batch 3 and worked up by Toolset II.Here it is the Cu-content of outer plate C 6568 thathas been switched from group ‘A’, dominant for Tool-set II, to ‘B’ else significant for Toolset I (see Table 9,

Table 10. The weight of the individual batches of silver: 8,778.5 gin all. Based on data from Tables 3 and 7.


Fig. 32. Correlation of copper content and lead isotope ratio in the parts of the cauldron.

Fig. 21 & Fig. 32). The original thickness ‘a’ of C6568 is consistent with the other plates worked up byToolset II, so the switch must have been done beforethe ingot was hammered out to a plate. Perhaps a bitcomplicated, it is imagined that the work group ofToolset II gave the piece of silver from batch 3 usedfor C 6568 to the work group of Toolset I, who thenadded copper to the melt, so that the Cu-contentwould become ‘B’, before the cast ingot was givenback to the work group of Toolset II, who then ham-mered it out to thickness ‘a’.

ANOMALIES IN RELATION TO THICKNESS AND

WEIGHT

As for outer plate C 6567 and inner plate C 6575,made out of batch 4, the problem is simpler. Bothplates have a Cu-content of ‘A’, indicating that theiringots were cast by the work group of Toolset II, whokept the one for C 6575, while the one for C 6567was given to the work group of Toolset I, before theingots were hammered out to a thickness consistentwith the rest of the plates in the two groups.

The inner plate C 6574 of Toolset I is the onlyplate of the 12 inner and outer plates whose thicknessdiverges from the others in the groups as it is an ‘a’while the rest of the group has thickness ‘b’ as men-tioned above in the section ‘Thickness of the silverparts’. At the same time, it is the widest of all plates,measuring 44 cm, and drawn on all four sides thoughtwo of its edges are also upset (see Table 4). Further-more, the weight of the plate of 383.2 g falls betweenthe weight of the other inner plates (402.1–438.7 g)and the outer plates (298.5–350.2 g). All these factorsmake the plate quite a puzzle, but maybe it was thelast plate to be made so all five inner plates could fitthe circumference of the bowl? Batch 1b was dividedinto four parts, of which plate C 6565 is the heaviestouter plate of all weighing 350.2 g, while C 6574 isthe lightest inner plate of all. If batch 1b had beendivided so that the ingot for C 6565 had become 20g less and the one for C 6574 had become 20 g heav-ier, they would have had the same weight as the aver-age weight of the outer plates of c. 330 g and theinner plates of c. 415 g. So maybe the answer to theanomaly of C 6574 is to be found in this dividing.


CONCLUSION

The uniform distribution of the batches of silver, Cu-content and thickness of the plates may indicate thatthe working up of the plates with Toolsets I and IIhas indeed been done by two work groups each con-sisting of one or more silversmiths, who had their ownbatches of raw silver at hand and understood by heartto mix copper in the silver so that a certain percen-tage could be obtained in the alloy, and further, tohammer out the cast ingots to plates of a certain uni-form thickness.

The anomalies of the three plates C 6567, C 6568and C 6572 may be explained by an exchange ofgoods and labour as follows. Straight forward thework group of Toolset II has delivered the ingot forC 6567 to the work group of Toolset I, who has thenhammered it out. This ingot consists, in goods andlabour, of both the raw silver and copper for the alloy,the melting of this and the casting of the ingot itself.Instead of the work group of Toolset I simply re-turning an ingot, for some reason or another, it hasreturned goods and labour equal to an ingot to makeends meet. This include the raw silver from batch 1bused by the work group of Toolset II for plate C 6572together with adding the copper, melting the alloyand casting the ingot for plate C 6568, for which thework group of Toolset II itself had delivered the rawsilver from batch 3. To conclude, we do not know ifperhaps the exchange was done the other way aroundor why the exchange was done at all. However, wecan say that this exchange is a proof of an interweav-ing of work procedures, which strongly indicate theidea of contemporary actions and close collaborationof several craftsmen in the making of the cauldron.

INVESTIGATION OF THE IRON RING FROMTHE RIMAs mentioned in the introduction, a slightly curvedpiece of iron from the rim of the cauldron has beenpreserved. Its length is now 9.5 cm, the weight is 60.1g, indicating that a good deal of metallic iron stillremains (Fig. 33). When found the iron core was sur-rounded by a silver tube, i.e., a fragment of the rim.This iron core once made out a very important partof the cauldron, in that the upper edges of the plateswere inserted into a notch in the iron. Without this

Fig. 33. Cross section of the iron core indicating that it may oncehave been shaped as a curved tube, not massively forged. Photo:

Arne Jouttijärvi, Heimdal-archaeometry.

iron reinforcement the cauldron with its thin plateswould simply have been damaged or deformed, forinstance, when filled with liquid. Moreover, the re-inforcement was necessary when making the suspen-sion.

The piece of iron is in several respects informative.A photo of a section of the iron core (Fig. 33) showsthat less than 10% is corroded. Considering that thering was placed inside the silver rim with which itwould make up a voltaic cell accelerating corrosion,in particular in moist surroundings rich in oxygen,most of the iron core would have been converted intorust if the cauldron was deposited on the surface, asusually suggested. If, in contrast, the cauldron wasdug into the bog, as now suggested (see the section byCharlie Christensen), the anaerobic conditions withpractically no oxygen would slow down corrosionvery much.

Metallurgical investigations showed that the ironhad a carbon content varying between c. 0,7–0,8%,i.e. was steel. Chemical analyses of 28 slag inclusionsshowed a very low content of phosphorus, less than0,1%. This is an important point excluding that theiron core was made of bog iron from an area embrac-ing present day Denmark, because all iron slag fromthis area, which so far have been analysed are charac-terised by a high content of phosphorus.

Lead isotope analyses of the iron core undertakenby Thomas Kokfeldt, Danish Lithosphere Centre,


Fig. 34. Chromatogram of organic material from the back of plateC 6571. The chromatogram shows, besides palmitic acid (P) andstearic acid (S), long chain fatty acids: tetra-, hexa- and octacosano-ic acid, together with the C25 – C 31 alkenes. This is characteristic

of beeswax.

University of Copenhagen, correspond nicely to thoseobtained from the Gundestrup cauldron silver. How-ever, it has been suggested that a diffusion of leadmight have taken place from the silver tube to theiron rod (personal comm. Z.A. Stos). If this is thecase, lead isotope measurements from the iron rodcannot be used to determine the region of origin ofthe iron. As for the accelerator dating of the iron coresee the corresponding section below.

ANALYSES OF THE ‘BLACK SUBSTANCE’Four samples were taken from the pitch-like materialon the reverse of the plates of the Gundestrup caul-dron (C 6571, C 6572, C 6573, and C 6574). As theanalyses, employing GC/MS (Gas chromatography –mass spectrometry) gave the same result, they will bedescribed together departing from the sample fromthe plate C 6571 (Fig. 34).

Using gas chromatography, volatile componentsare separated. The mass spectrometer connected tothe gas chromatograph is used as a sensitive detectorand analyser of components found. To make compo-nents volatile it is often necessary to derivative these.In this case, this was done by using basic hydrolysisovernight at room temperature, acidifying the result-ing solution, and, finally, extracting material with di-ethyl ether. The ether extract was then methylatedusing diazomethane, and analysed.

The material mainly contains palmitic acids (Fig.34 peak P) and stearic acids (Fig. 34 peak S), togetherwith long chain fatty acids and alkenes. The latter arecollected together under ‘Long chain fatty acids andalkenes’ on Fig. 34. All components, as well as theproportions between them, are characteristic for bees-wax, which is therefore the content of all foursamples. Besides, all four samples were thoroughlyexamined for the presence of tar or resin components.These were not found in any of the samples.

THE ACCELERATOR DATINGConsidering that the archaeological dating of theGundestrup cauldron remains disputable, a crucialpoint of the new investigations were attempts one wayor another, to obtain a more exact date, employingnatural scientific methods. A common choice for ar-chaeological dating is the radiocarbon method, whichdetermines the age of organic materials from thegradual disappearance of the radioactive isotope car-bon-14 (14C) by radioactive decay. 14C is producedcontinuously by the interaction of cosmic radiationwith nitrogen in the atmosphere, and it is present inmore or less constant concentrations in the atmos-phere and in carbon reservoirs, such as the biosphereand the oceans, in open exchange with the atmos-phere. After this exchange stops, the concentration of14C decreases by radioactive decay with a half-life of5730 years, the time period at which this began tohappen can be determined.

In accelerator mass spectrometry (AMS), a high ac-celerating voltage – in the million volt range insteadof the kilo volts of regular mass spectrometry – pro-vides the energy needed to eliminate unwanted ionshaving the same mass as 14C and thus allows the ac-curate measurement of 14C abundances in the naturalrange of 10ª12 to 10ª15, i.e., 1 14C atom per 1012 to1015 carbon atoms. This mass spectrometric measure-ment offers a roughly 10,000-fold increase in sensi-tivity over conventional 14C dating, as it directly de-tects all 14C atoms instead of only those that decayduring the measurement (roughly 1 14C atom out of1 million decays in a 3-day measuring period). Thussamples in the sub-milligram range can still be ana-lysed.

The problem that radiocarbon dating of the Gun-


destrup cauldron requires carbon was solved by thesmall amounts of organic material to be found in con-cavities on the back of all plates. This idea becameeven more attractive when the analyses by J. Gla-strup, see above section, had proved that the materialin question was beeswax, which, most conveniently,has a very low age of its own and thus would provideexcellent material for radiocarbon dating. As the or-ganic traces remaining on the plates of the cauldronwere in the sub-milligram range, only acceleratormass spectrometry (AMS) could be used for dating.Also, it was decided to try and date a sample of ironfrom the rim (see above) by measuring the residues ofcarbon in the iron.

PURIFICATION OF THE BEESWAX SAMPLES

As described earlier, conservation lacquer had beenapplied to the plates, possibly more than once. Thussampling the plates for radiocarbon dating not onlyinvolved collecting enough beeswax for an AMSmeasurement, but also making sure that this wax didnot incorporate traces of conservation lacquer. Thesamples were taken to the Department of Conser-vation at the National Museum of Denmark and puri-fied by Ulrich Schnell, but at first each sample wassplit into two as a security precaution. Consequently,the measuring uncertainty for very small sampleswould become greater. A part of the contaminant ofthe beeswax was seen in the microscope as black par-ticles thought to be remnants of soot from the processof melting the beeswax out from the back of the plates

Table 11. Samples of beeswax and samples of beeswax residueswith varnish particles selected for AMS 14C dating.

over a hearth after finishing the repousse work. Thissoot could give an older age of the beeswax as a resultof an older age of the wood used in the fire. For puri-fication, the beeswax with lacquer particles was melt-ed under a nitrogen atmosphere, distilled and allowedto separate in clean, pre-baked fused Vitrex capillarytubes, which yielded clean beeswax in one end andremnants of beeswax with lacquer particles in theother end of the capillary tubes. Subsequently thetubes were broken at the visual parting line of the twoto give a set of clean beeswax samples plus a secondset with remnants of beeswax and lacquer particles(called residues in the following).

AMS 14C DATING OF THE BEESWAX

A set of four sample pairs from four plates showingsigns of two different toolsets was sent to the LeibnizLabor für Altersbestimmung und Isotopenforschung,Christian-Albrechts-Universität in Kiel (Table 11).Because of the very small amount of available samplematerial the samples have been combined in pairs(see Table 12). The wax and residue samples weresealed in their glass capillaries – without pretreat-ment – into closed quartz tubes together with CuOand silver wool and combusted at 900 æC. The CO2

of all samples were reduced with hydrogen over ironpowder as catalyst, and the resulting carbon/ironmixture were pressed into pellets in the target holders.

As was expected, samples KIA19707, 19708,19713, and 19714 gave very small amounts of carbon(∂0.1 mg C–0.26 mg C, calculated from CO2 press-

Table 12. Combined toolset samples of Table 11 selected for AMS14C dating.


Fig. 35. Conversion of radiocarbon age into calibrated age ofKIA19713, beeswax from plates C 6571 and C 6574. The cali-brated age is according to CALIB rev 4.3, Data set 2 (Stuiver et

al. 1998).

ure). They were reduced on 1 mg Fe, instead of theusual 2 mg, to obtain a better C:Fe ratio. Still, thetargets produced substandard ion beams during theAMS-measurement (20% to 45% max [KIA19713]of the average ion beam of a normal 1 mg carbonsample). The 14C concentration of the samples wasmeasured by comparing the simultaneously collected14C, 13C, and 12C beams of each sample with thoseof Oxalic Acid standard CO2 and coal backgroundmaterial (Nadeau et al. 1997). After appropriate beamintensity corrections, the d13C values are in the nor-mal range.

Conventional 14C ages were calculated accordingto Stuiver and Polach (1977) with a d13C correctionfor isotopic fractionation based on the 13C/12C ratiomeasured by our AMS-system simultaneously withthe 14C/12C ratio (note: This d13C includes the effectsof fractionation during graphitization and in theAMS-system and, therefore, cannot be comparedwith d13C values obtained per mass spectrometer onCO2). For the determination of our measuring uncer-

tainty (standard deviation s) we observe both thecounting statistics of the 14C measurement and thevariability of the interval results that, together, makeup one measurement. The larger of the two isadopted as measuring uncertainty. To this we add theuncertainty connected with the subtraction of our‘blank’. The quoted 1s uncertainty is thus our bestestimate for the full measurement and not just ourcounting statistics. ‘Calibrated’ or calendar ages werecalculated using ‘CALIB rev 4.3’, Data set 2, 1998decadal atmospheric data (Stuiver et al. 1998).

The measured and calculated values of the samplesare summarized in Table 13. Figs. 35 shows the trans-lation of the measured 14C age for sample KIA19713,with its symmetrical gaussian probability distributionfor the ‘true’ 14C age, into calibrated age (BC/AD)with an irregular probability distribution for ‘true’calendar age, due to the irregular tree ring calibrationcurve. The probability distributions of the calibrated‘true’ ages of all samples are graphically summarizedin Fig. 36.

In view of the small amount of carbon, the beeswaxresults should be interpreted with great care and arenot easy to interpret. They give a grouping of thewax of Toolkit II with two residue dates, which areconsistent, but younger than the single ‘outlier’, i.e.,the wax date for Toolkit I, which is significantly olderthan the others. This single sample is the largest (0.26mg C, about twice the amount of Toolkit II wax) andgave a significantly larger ion beam (45% instead ofthe 32% of a ‘normal’-sized sample obtained forToolkit II, or 20% for the residues). There is thusreason to believe this date is better than the others.The younger ages obtained for the other wax samplesmight then be attributed to their very small size andion current and/or to contaminants.

AMS 14C DATING OF THE IRON

A sample (KIA25400) from the iron rim of the caul-dron (Inv. No. C 6576 C) was, in a still experimentalprocedure, also subjected to 14C AMS. The ironsample was cleaned mechanically from rust and con-servation material and subjected to a soxhlet typeserial extraction to remove non-polar organic con-taminants (Bruhn et al. 2001). In sequence, the con-taminants were extracted three times each with boil-


Fig. 36. Range of calibrated AMS 14C dated samples from the Gundestrup cauldron. KIA19713 is considered the most reliable beeswaxsample at present. Calibrated age against CALIB rev 4.3, Data set 2 (Stuiver et al. 1998).

ing tetrahydrofurane (THF), chloroform, petroleum-taminants (Bruhn et al. 2001). In sequence, the conde-mineralised water. To further clean the surface fromtraces of metal sampling tools, the sample was etchedwith 1% HCl in an ultrasonic bath, washed in demin-eralised water and acetone and finally dried. The car-bon in the cleaned sample was combusted to CO2 ina closed quartz tube together with CuO at 1000 æCfor 24 h. To remove sulphur from the sample gas, theCO2 gas was trapped and sealed again with CuO andsilver wool and combusted at 900 æC. The CO2 of thesample was reduced with hydrogen over iron powder

Table 13. Measured and calibrated values of the AMS 14C dated samples.

as catalyst, and the resulting carbon/iron mixture waspressed into a pellet in the target holder.

Sample KIA25400 gave more than the 1 mg ofcarbon recommended for a precise measurement andproduced sufficient ion beam. The d13C value is inthe normal range and insofar the result is reliable.The conventional 14C age and calibrated age forKIA25400 were calculated in the same way as thoseof the beeswax and the measured and calculatedvalues are shown in Table 13. The the resulting curveof the translation into calibrated age is shown in thesummarizing Fig. 36.


The iron date is significantly older than any of theother samples (∂BC 380–200). It should be noted,that the extraction of carbon from iron and its 14C-AMS measurement is not yet a routine method inthe Leibniz-Laboratory and the radiocarbon date ofsample KIA25400 should therefore be interpretedwith care. The main problem is that the carbon ex-tracted from the iron may come from differentsources and may be re-melted older iron. The ironmay thus contain not only contemporaneous charcoalcarbon from the smelting process, but also carbonfrom flux material (e.g. carbonate, lime), which mostlikely is older and will complicate the interpretation.Contamination of an iron sample during cutting ormilling with traces of modern steel, containing fossilcarbon, cannot be excluded. To minimize this lattercontamination, we used the sample supplied as awhole, without further cutting, and leached it withHCl to remove the surface layer with its possibletraces of contaminant. Parallel pretreatment of aniron sample with a known age, which was cut toabout the same sample size, and subsequent AMS ra-diocarbon measurement gave no indication of sig-nificant contamination. Although these results arepromising, they do not yet provide sufficient proofthat the 14C ages obtained on iron are as reliable asages obtained on normal dating materials. The olderage of the iron is not inconsistent with the other dates,but may be seen as evidence for the use of older woodand/or flux, or, of older iron to construct the rim, oras a trace of modern tool-iron with fossil carbon.

BOG GEOLOGICAL INVESTIGATION INRÆVEMOSEN 2002One month after finding of the Gundestrup cauldron,local people supervised by the vicar and on requestfrom the National Museum, cut out a section of intactpeat only c. 0.60 m from the finding place of the caul-dron. The section measured c. 1.2 m from the surfacedown to c. 0.3 m below the cauldron, the parts ofwhich had been found dismantled c. 0.6 m below thesurface (Larsen 1995, 98 f). The section was carefullypacked and forwarded to Emil Rostrup, Reader at theUniversity of Copenhagen, and one of the leadingbotanists of his time.

Rostrup’s analyses of the plant remains, quoted by

Müller (1892, 37), indicated that in the Iron Age thecauldron had been deposited on a firm bog surfacewhich could be plied, vegetated with Sedge (Carex),Deergrass (Scirpus caespitotus), Sphagnum, Clubmoss (Ly-

copodium), as well as bushes, i.e., Birch (Betula) and Ju-niper (Juniperus). Remains of water plants were notfound, and the composition of the vegetation thuscharacteristic of what is met in a common heath bog.

Juniperus does not grow on bog soil, for which reasonthe twigs/branches found from this species, and maybefrom Betula too, could have been placed in connectionwith the deposition of the cauldron. The twigs/branches were exclusively found in the same level asthe cauldron, and such an accumulation of twigs/branches, whether representing a man-made event,thrown into a peat pit, or a natural bush stage in thedevelopment of the bog would likely be found during arenewed investigation in the bog. If the stratigraphicalposition of the cauldron could be established in thisway, 14C dating of plant remains from the layers, forinstance, sprigs from Juniper, might contribute to fix thetime of the deposition of the cauldron. It should bementioned that the section taken out in 1891 has beensearched in vain at the University.

In 2002, an investigation aiming at illuminating theabove-mentioned issues was carried out in theRævemose by the National Museum, assisted by thelocal Vesthimmerlands Museum. The finding place of thecauldron was established as precisely as possible usingall existing information about its position, i.e., c. 12.5m north of the erected memorial stone of the find ofthe cauldron. 15 borings were made along a line run-ning east – west, departing from firm ground and 25m into the bog. The finding place was situated 18 mfrom firm ground on this line. In a line running northfrom the finding place, borings were undertaken 1, 3,5 and 7 m from the place. South of the finding placeborings were not undertaken, since a sketch from1891 clearly indicates that this area had been dugaway before the cauldron was found. The augers em-ployed were of a kind securing undisturbed samples.

It was assumed that around the finding place thepeat would have been completely removed until be-low the position of the cauldron, but that some dis-tance away one could hope to reach still intact layers.This did not happen, however, and there were nosignificant stratigraphical differences in any of the


borings as far as the upper 1.5 m is concerned. Nei-ther could contours of peat pits or balks in betweenthese be recognized, whether as a difference in levelor the vegetation of the bog. Admittedly, a distinctionbetween more wet areas vegetated with Bog-myrtle(Myrcia gale), Sphagnum and more dry ones dominatedby Hare’s-tail (Eriophorum vaginatum) could be seen, butwhen boring, there were no stratigraphical differencesbetween the two types of vegetation, just as their bor-derlines were not rectilinear.

On an aerial-photo from 1954 the bog surface ap-pears with numerous traces after peat pits. Since thattime the balks between the peat pits must have disap-peared through a long period of destruction and col-lapse, when the water level in the bog is known tohave been low. The present high water level furtherhelps to blur previous peat digging.

So far, further pollen analyses of the boringsamples have not been undertaken. After the newfield investigation it can only be concluded, that allover the bog up to two meters of peat have been dugaway, or destructed by drying up and humification,and that the level of the finding place is now situatedabove the present bog surface. (Considering the treas-ure trove paid to the finders of the cauldron, the moti-vation to increase peat digging was certainly aug-mented).

A little more than a month after the cauldron wasfound First Lieutenant Daniel Bruun, who since thenhad acted on behalf of the National Museum, re-ported to this institution about the find and the findcircumstances. After information from the peat dig-gers, Bruun, in his report, wrote that the depth of thebog varies from a few inches to c. three metres, yetwith considerable variation (Larsen 1995, 65ff; Müller1892, 37).

However, the borings in 2002 showed that belowthe peat layers a Post-glacial gyttja layer from a lake-stadium is encountered, and even Late-glacial layershave been demonstrated. On the finding place, thebottom is not met until 3 m below present surface.The border between the gyttja and the superimposedpeat, i.e., the shift from lake to bog according to theborings undertaken, is situated around 1.2 m belowthe surface. The shift in question, through a prelimi-nary pollen analysis, can be placed in the Atlanticperiod, between 6.000 and 4.000 BC.

Bruun further wrote that around the finding placemany trunks were observed, often charred or withstrokes from axes. Actually, by borings in 2002, a pinetrunk was found at the bottom of the peat. Trunkswith strokes from axes may indicate Prehistoric peatdigging in the bog. It has several times been observedthat in the Pre-Roman Iron Age that soft trunks werecut if they hindered peat digging.

Since Rostrup’s investigation it has always been as-sumed that the cauldron was placed on a dry surfacein the bog, one on which man could walk. This, how-ever, is disputable, since a new estimation of the ex-tent of Iron Age peat digging and the frequency ofuse of small and large peat pits as later offerings/depositions has recently been presented (Christen-sen & Fiedel 2003, 85ff). A sketch by Bruun made onthe basis of information from the finders (Fig. 37)shows a strange looking, loose area, almost a hollow,in the peat immediately above the cauldron. It is dif-ficult to explain the presence of such a hollow by laterpeat formation on the surface of the bog.

If, in fact, the cauldron was placed in a pit in thebog, the formation of the hollow may be explained intwo ways. When growing over of a water- filled pit,Sphagnum would spread across the sheet of water, re-sulting in formation of a very loose peat in the lower-most parts of the pit. Alternatively, after the depo-sition of the cauldron the upper part of the sides ofthe pit would eventually collapse and fall toward thecentre; a combination of the two is imaginable too.

Such naturally overgrown pits can in many casesbe difficult to recognize by non-experts. Hence, it isnot improbable that the Gundestrup cauldron, likethe bog corpses and numerous other depositions,were placed in an old peat pit, or one especially dugfor the purpose of the cauldron. If so, the section ofpeat dug out in 1891 must have been removed fromoutside the pit since it only contained peat created ona rather dry soil.

In the 2002-investigation of the bog, the employ-ment of metal detectors was also undertaken in thehope that missing parts of the cauldron might turnup, although the acidity of the bog borders on whatiron would tolerate. In the very wet bog detecting wascarried out from plates of heavy plywood; an area upto 10–20 m from the determined finding place wasvery thoroughly examined. A magnetometer was


Fig. 37. In his report to the National Museum from the beginningof June 1891 Daniel Bruun had made this sketchy section N-S ofthe finding place. The figures to the left indicate alen (one alen is0.627 m). The hollow, i.e. the area of looser peat above the bowl

of the cauldron is marked with an ‘‘a’’.

used, which can record iron down to a depth of 1.5metres, depending on the size of a given object.Moreover, also a common metal detector was em-ployed, which records metals down to 30–40 cm.Nothing was found, however, which was neither tobe expected if the above interpretation is correct: thatthe layers in which possible remaining objects may befound are simply no longer present in the bog.

CONCLUDING REMARKSScientists representing no less than seven different na-tionalities have, in one way or another, been involvedin the work briefly discussed above. This internationalco-operation, being as cosmopolitan as the Gunde-strup cauldron itself, has been most stimulating, andscientifically very rewarding. No doubt, the results ob-tained will contribute much to our understanding ofthe Gundestrup cauldron. When all the new resultsobtained have been considered, as well as researchstill in progress, it is time for further reflections on theessence of this remarkable object.

If possible, the ultimate aim of the efforts ought tobe the publication of a monograph where all scholarsinvolved are invited to contribute, allowing for a thor-ough documentation of the studies carried out as wellas comments on the implications of recent research.Consequently, this is not the place to commence a

general discussion of the many aspects, which em-brace this research. Nor is it convenient yet to dealwith the purely archaeological, i.e., cultural andchronological issues, beyond a few comments on re-search that needs to be undertaken. This has to dowith the fact that the issues in question remain mostintriguing and far-reaching. Anyhow, in this conclus-ive section it may at least be appropriate to sketch outwhich research remains to be undertaken, or is al-ready in progress.

First of all, more accelerator datings are needed,and such datings are actually under way from theLeibniz Labor in Kiel. Without safe scientific datings,discussions about the age of the cauldron may nevercease. Since it has been proved that the dark, organicmaterial on the backside of some of the plates is actu-ally beeswax, it would be logical also to attempt toundertake a DNA analysis of this material.

A considerable number of lead isotope analyses ofsilver from the cauldron are now at disposal, but morereference material is needed in order to discuss theorigin of the Gundestrup silver on a sound basis. Suchdata should consist of lead isotope analyses of se-lected, relevant silver objects of the period. Evenmore interesting would be lead isotope analyses fromvarious silver sources which were mined in BarbarianEurope in the centuries around the birth of Christ; fora short recent survey of these sources and associatedproblems, e.g., see P.T. Craddock (Craddock 1995,211ff). In order to get up to date information aboutthis complicated field of research, it is obvious to in-itiate such a project in France and Germany andother countries in collaboration with local experts.According to Z.A. Stos findings above, it is probablyfrom within these geographical areas that the Gun-destrup silver derives. Anyhow, lead isotope analysesof the silver from all individual parts of the Gundestr-up cauldron is now at disposal to our colleaguesabroad. Maybe the analyses can already be of someuse.

Strictly archaeologically, much remains also to bedone, including thorough, modern, iconographic andart historical analyses of the imagery of the cauldron,among other things in order to grasp the bewilderingmedley of styles, ranging from primitive and ‘bar-barian’ to sophisticated and even naturalistic. Onewould also have to reflect on why the cauldron was


produced and on the person(s) behind this remarkableinitiative. This leads on to the questions of the exist-ence of a possible workshop and how this may havebeen organized, including how the craftsmen of itwere operating. Employing the results of the newscientific research can illuminate this last point,among others. Questions associated with the work-shop may also be answered in a more general way byconsulting certain written sources. Indeed, a precari-ous labour lies ahead, inevitably embracing most ofthe sticking points, which have been debated for ages,including the question of the ‘origin’ of the Gunde-strup cauldron.

This question makes an excellent opportunity tostate that putting wrong questions leads to wronganswers, as I have previously argued in the case of thecauldron (Nielsen 1999, 186), departing from other,similarly intriguing, questions of origin within Prehis-tory. In the case of the Gundestrup cauldron, onemight ask: The origins of what? Is it the silver itself,the tin used when soldering the different parts to-gether, the gold (gilt), or the glass eyes of the outerplates? Or, is it the ‘cultural’ backgrounds of the indi-vidual artists who apparently were involved in themaking of the cauldron, which is under discussion?As will be understood, there is no simple answer tothe question of origin.

This leads on to a discussion whether it is at allexpedient to associate the Gundestrup cauldron witha certain ethnicity, be it Celtic, Thracian, both, orsomething else, as has so often been done in thecourse of time. I would much prefer to restrict notionslike Celtic and Thracian to the realms of history andlinguistics, or to such archaeological topics where theycan be meaningfully discussed. Apparently, this is notpossible in the case of the Gundestrup cauldron,where such designations are inoperable, as it will bebriefly argued in the following.

It should be understood that ethnicity in Europe atthe time of the Gundestrup cauldron, i.e., cautiouslythe centuries around the birth of Christ, constitutes acomplex and most bewildering picture. This was, aswill be remembered, an era where large-scale mi-grations of Celts, Germanic and other people affectedconsiderable parts of the Continent. Neither shouldthe Roman expansion and numerous associated cam-paigns be forgotten, nor the subsequent Romaniza-

tion. Moreover, in the case of campaigns, foreign aux-illaries often participated. These historical events,where people of different ethnic background, influ-enced the attitudes of the societies involved, not leastin art, is probably what one encounters in the imageson the Gundestrup cauldron.

Finally, the traditional, archaeological dating of theGundestrup cauldron versus the accelerator datingsshould be briefly discussed. Traditional surveys deal-ing with archaeological datings of the cauldron byvarious scholars range from ca. 200 BC. to ca. 300AD (for the most recent discussion, see Falkenstein2004, Abb. 2, with further references). It is almostsuperfluous to mention that this remarkable, chrono-logical disagreement among scholars has to do withthe sad fact that none of the various objects depicted,torques, helmets, shields, swords, lances, spurs,phalerae, carnyxes etc. can be sufficiently exactly dat-ed. This also embraces the widely different motifs onthe cauldron, all hard to deal with chronologically.

Turning to the accelerator datings, the problemswith the one consisting of carbon residue from theiron core of the rim has been discussed in the respect-ive section above. This dating will not be dealt withany further since it is probably archaeologically un-tenable.

Looking at the accelerator datings of beeswax fromthe backs of the plates, four in number (Fig. 36), theseall place the Gundestrup cauldron in the Roman IronAge, i.e., 1 AD–400 AD, with only a possible limitedoverrun to neighbouring periods. At present, it is inparticular sample KIA19713, which should be con-sidered being the most reliable one.

In fact, accelerator datings of the Roman Iron Ageare not that surprising since a similar date has beensuggested by several scholars in the course of time(Falkenstein loc.cit.). For instance, Sophus Müller(Müller 1933, 44f), when discussing the Gundestrupcauldron for the last time, convincingly argued thatthe Gundestrup cauldron ‘‘should be understood as awork from the earliest Roman period’’, my trans-lation. In the context, this means after the birth ofChrist, i.e., 1st century AD. Among other things,Müller states ‘‘this is art of barbarian character, notan initial development, but with basis in the classical’’,my translation. Furthermore, he points to inspirationfrom Roman art. Previously, Müller did not even ex-


clude a date of the Gundestrup cauldron to the 2ndcentury AD (1897, 574). That the cauldron couldpossibly be dated even later, ‘‘in einer Zeit die derjüngeren römische Kaiserzeit entspricht’’ was sug-gested by H. Norling-Christensen (1966, 406).

In conclusion, the present writer suggests a dating

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Author’s addresses

Jan Holme Andersen, ConservatorThe Royal Danish Academy of Fine ArtsSchool of ConservationEsplanaden 34DK-1263 Copenhagen KDenmarkjha/kons.dk

Joel A. Baker, PhDDanish Lithosphere CentreØster Voldgade 101350 Copenhagen KDenmark– andSchool of Earth SciencesVictoria University of WellingtonP.O. Box 600WellingtonNew Zealand

Charlie Christensen, Cand. Scient.National Museum of DenmarkNy Vestergade 11DK-1471 Copenhagen KDenmarkCharlie.Christensen/natmus.dk

Jens Glastrup, Cand. Scient.National Museum of DenmarkDepartment of Conservation, LaboratoryP.O. Box 260DK-2800 Kgs. LyngbyDenmarkjens.glastrup/natmus.dk

Pieter M. Grootes, Dr.Leibniz LaborChristian-Albrechts-UniversitätMax-Eyth Strasse 1124118 KielGermanypgrootes/leibniz.uni-kiel.de

Matthias Hüls, Dr.Leibniz LaborChristian-Albrechts-UniversitätMax-Eyth Strasse 1124118 KielGermany

Arne Jouttijärvi, MSC in EngineeringHeimdal-archaeometrySkovledet 30DK-2830, VirumDenmarkheimdal/archaeometry.dk

Erling Benner Larsen, ConservatorBrandstrupvej 10DK-4293 DianalundDenmarkbennerlarsen/mail.dk

Helge Brinch Madsen, Conservator, Cand. Phil.The Royal Danish Academy of Fine ArtsSchool of ConservationEsplanaden 34DK-1263 Copenhagen KDenmarkhbm/kons.dk

Katharina Müller, Dipl.-Chem.Technische Universität BerlinInstitut für ChemieStrasse des 17. Juni 13510623 BerlinGermany

Marie-Josee Nadeau, Dr.Leibniz LaborChristian-Albrechts-UniversitätMax-Eyth Strasse 1124118 KielGermanymnadeau/leibniz.uni-kiel.de

Svend Nielsen, MA & Dr.phil.National Museum of DenmarkFrederiksholms Kanal 12DK-1220 Copenhagen KDenmarksvankaer/stofanet.dk

Stefan Röhrs, Dipl.-Chem.Technische Universität BerlinInstitut für ChemieStrasse des 17. Juni 13510623 BerlinGermany


Heike Stege, Dr.Doerner-InstitutBayrische StaatsgemäldesammlungenBarer Strasse 2980799 MunichGermanystege/doernerinstitut.dk

Zofia Anna Stos, Dr.Research Laboratory for Archaeology and the History of ArtUniversity of Oxford6 Keble RoadOxford OX1 3QJ– andUniSdirectUniversity of SurreySenate House, GuildfordSurrey GU2 7XHUnited KingdomS.Stos/surrey.ac.uk

NOTE IN PRESS

The final accelerator dates of beeswax (larger samplesthan previously) from the Gundestrup cauldron havebeen received from Leibniz Labor für Altersbestim-mung und Isotopenforschung, Christian-Albrechts-Universität, Kiel.

KIA 27547 gives BP 2448∫21, calibrated BC 536,533, 519.

KIA 27548 gives BP 2267∫36, calibrated BC 379.Professor P.M. Grootes of the laboratory states

(Oct. 5, 2005): ‘‘The new measurements producedunexpected results, significantly older than the pre-vious wax ones. At the moment, I see no way to rec-oncile the results. In my opinion, the earlier measure-

Tod E. Waight, PhDDanish Lithosphere CenterGeological InstituteUniversity of CopenhagenØster Voldgade 10 LDK-1350 Copenhagen KDenmarktodw/geol.ku.dk

ments are valid, although the small sample size re-sulted in enlarged uncertainty. Those measurementsdid not give indication of a large age-difference be-tween possible contaminants in the residue and thewax. The younger age of the residue [KIA 27548,editorial addition], as compared to the wax [KIA27547, editorial addition], argues against contami-nation by petrochemical, old varnish particles.’’

It should be noted that the two results for residue,KIA 25400 (earlier date, see main text with Table13 & Fig. 36) and KIA 27548 (date in press) – bothrelatively large samples – are nearly identical (fourth-third century BC) [editorial note].


Cf. Fig. 6. The Bull plate C 6563, 25 cm in diameter, from the bottom of the cauldron – a masterwork of repousse work originally gilt onthe whole surface. Recent studies of toolmarks show that different tools probably in different hands have been involved in its making. Onthe photo the inserted numerals 1 to 10 are used as references in the text to observations of details. At last three different hands have thus

been involved – maybe even more. In the future work we have to reconsider the grouping of tool marks and surface textures.

Documents

The Gundestrup Cauldron