Analysis and Interpretation of a Unique Arabic Finger Ring from theViking Age Town of Birka, Sweden

SEBASTIAN K.T.S. WA RMLA NDER,1,2 LINDA WA HLANDER,3 RAGNAR SAAGE,4 KHODADAD REZAKHANI,5SAIED A. HAMID HASSAN,6 AND MICHAEL NEI7

1Division of Biophysics, Arrhenius Laboratories, Stockholm University, Sweden2UCLA/Getty Conservation Programme, Cotsen Institute of Archaeology, UCLA, Los Angeles, California3Swedish History Museum, Stockholm, Sweden4Department of Archaeology, University of Tartu, Estonia5Institute of Iranian Studies, Freie Universitat Berlin, Germany6Supreme Council of Antiquities, Ministry of Antiquities, Cairo, Egypt7Department of Archaeology and Ancient History, Uppsala University, Sweden

Summary: In this work we used non-destructive SEMimaging and EDS analysis to characterize the materialcomposition of an Arabic finger ring, which was foundin a 9th c. womans grave at the Viking Age (A.D. 7931066) trading center of Birka, Sweden. The ring is setwith a violet stone inscribed with Arabic Kufic writing,here interpreted as reading il-la-lah, i.e. For/toAllah. The stone was previously thought to be anamethyst, but the current results show it to be colouredglass. The ring has been cast in a high-grade silver alloy(94.5/5.5 Ag/Cu) and retains the post-casting marksfrom the filing done to remove flash and mold lines.Thus, the ring has rarely been worn, and likely passedfrom the silversmith to the woman buried at Birka withfew owners in between. The ring may thereforeconstitute material evidence for direct interactionsbetween Viking Age Scandinavia and the Islamicworld. Being the only ring with an Arabic inscriptionfound at a Scandinavian archaeological site, it is aunique object among Swedish Viking Age material. Thetechnical analysis presented here provides a betterunderstanding of the properties and background of thisintriguing piece of jewelry. SCANNING 9999:XXXX,2015. 2015 Wiley Periodicals, Inc.

Key words: scanning electron microscopy (SEM),archaeology, Allah, Kufic Arabic, Islamic jewelry

Introduction

Birka, often considered Swedens first town, had astrategic location on the island Bjorko, 25 km west ofmodern-day Stockholm (Ambrosiani, 2012). Archaeo-logical excavations of Birka have unearthed numerousobjects from distant places, testifying to Birkasimportance as a trading center during the Viking Age(A.D. 7931066) (cf. Hagg, 83; Jansson, 85a, 88;Duczko, 97; Ambrosiani and Gustin, 2003; Sindbk2012; Ambrosiani, 2013). One of the most significantfinds is an Arabic-style finger ring (Fig. 1), found byarchaeologist Hjalmar Stolpe during the 18721895excavations of the Birka grave fields. This ring is nowhoused at the Swedish History Museum in Stockholm,where the inventory catalogue describes it as being ofgilded silver, set with a violet amethyst inscribed withthe word Allah in Arabic Kufic writing. Even though afew rings of similar design have been encountered atBirka and other archaeological sites (Jansson, 88), thisis the only Viking Age ring with an Arabic inscriptionfound in Scandinavia, which affords it a unique status.However, a proper technical analysis of the ring has sofar not been carried out, and its material composition hasbeen questioned. It was recently decided that a replica ofthe ring should be made, and this provided us with anopportunity to examine the ring using non-destructivemethods. Here, we present the results of this inves-tigation, which mainly is based on SEMEDS imagingand elemental analysis.

Contract grant sponsor: Helge Ax:son Johnson Foundation.Contract grant sponsor: Berit Wallenberg Foundation.Address for reprints: Sebastian K.T.S. Warmlander, Division of

Biophysics, Arrhenius Laboratories, Stockholm University, 106 91Stockholm, Sweden.Email: seb@dbb.su.se

Received 18 September 2014; Accepted with revision 29 December2014

DOI: 10.1002/sca.21189Published online XX Month Year in Wiley Online Library(wileyonlinelibrary.com).

SCANNING VOL. 9999, 17 (2015) Wiley Periodicals, Inc.

Materials

The ring was found in grave 515 (Swedish HistoryMuseum; SHM 34000, Bj 515; FID 106842), located ingrave field 2 A north of Borg on the Bjorko Island. Thegrave contained a rectangular wooden coffin, andalthough the skeleton was completely decomposed,the clothes, jewelry, an equal-armed brooch, and twocharacteristic oval brooches of type P 27b (Jansson,85b) show it to be a female burial dating to circa AD850. The ring was encountered where the womans chestwould have been, slightly below the right oval broochand next to a pair of scissors (Arbman, 55). From theleft oval brooch a needle case was hanging in a chain,and it seems possible that also the ring and the scissorshad been attached to the (right) oval brooch, i.e. with anow-lost string. Yet, as the burial position of the womanis unknown, it is also possible that she was laid to restwith her hands on her chest, and with the ring on one ofher fingers. Between the two brooches was a row ofbeads made from glass, rock crystal, and carnelian(Fig. S1). The last two materials could originate fromIndia or Caucasus, although also Yemen was known forits carnelian (Danielsson, 73; Arrhenius, 78; Jansson85b, cat. no 15). In addition, some of the glass beadshave a foreign appearance, and were likely imported.The womans brooches and clothing are however typicalScandinavian. The clothing included an undergarmentof flax and a garment of blue wool, likely dyed withwoad (Geijer, 38; Hagg, 74; Jansson, 85b).

The ring is a normal-size finger ring, measuring19 mm in outer shank diameter and 26 mm from thebottom of the shank to the top of the stone. It is made ofwhite metal, set with a pink/violet stone with an Arabicinscription (Fig. 1 and S2). The overall design, with fourlow prongs holding the oval cabochon-cut stone, is alsoArabic (Arne, 14; Jansson, 88). Three other rings ofthis design have been found at Birka: one as a stray findin the Black Earth, and the other two in graves Bj 526and 791 (Figs. S35). The ring in the latter gravedisplays flower ornamentation typical for the Seljuk

culture in Asia Minor. At Birka, it was not used as afinger-ring, but had been made into a decorative amulettogether with an added silver bead (Fig. S5). Other Birkafinds include a similar ring missing a stone, and a stoneof carnelian thought to belong to a ring (Fig. S6). Ringsof this Arabic type have furthermore been encounteredin trading posts in Eastern Europe, such as Polom,Poltava, and Verchnee Saltovo (Arne, 14, Figs. 326328), and in what appears to be a male grave in theTankeevka cemetery in Tatarstan (Androshchuk, 2013Fig. 81:4). These other rings do however not carryinscriptions. During the Viking Age rings with Arabicwriting are rather uncommon in Europe, and only ahandful have so far been encountered (Roman Kovalev,personal communication). The Birka ring is the only onefound in Scandinavia, and because of its engraving, ithas often been interpreted as a signet ring (Arne, 14;Arbman, 40; 55; Aiken and Arwidsson, 86).

Methods

The ring was examined with a standard opticalstereomicroscope (E. Leitz GmbH) as well as with atable-top Hitachi TM-3000 scanning electron micro-scope (SEM), operating at 15 kV and equipped forelemental analysis (SEMEDS). The SEM investigationwas done without coating the object, using high vacuum(10 5 Torr) for the metal surface analysis, and lowvacuum (10 3 Torr) for the analysis of the stone (toavoid charge build-up). SEM-EDS data was recordedfor five minutes at each measured point. Multiplephotographs of the ring, taken from different angles witha digital SLR camera (Canon EOS 600D), were stitchedtogether into a 3D model using the Agisoft PhotoScansoftware (Agisoft LLC, Russia).

Results

Photographs of the ring are shown in Fig. 1, and a 3Dmodel of the ring is shown in Fig. S8. Digital 3D models

Fig 1. Photographs of the studied ring, by Ragnar Saage and by Christer A hlin at the Swedish History Museum. Black line is 1 cm.

2 SCANNING VOL. 9999, 9999 (2015)

have previously proven useful for visualizing intricatedetails (Nei et al., 2014) and for accurate metricmeasurements (Sholts et al., 2011) of archaeologicalmaterial. The current 3D model is included to give thereader a better visual understanding of the ring. SEMimages of details of the ring are shown in Fig. 2.Remnants of organic material are present in the crevicesunder the stone (Fig. 2), which is not uncommon inarchaeologically excavated objects. The ring shank isbroken in three places, and the parts have been clumsilyglued together. SEM-EDS analysis showed the joins tocontain only organic material no traces of solderingmaterial were observed. It is not clear whether the ringwas broken when it was unearthed in the late 1800s, butit might have been. The appearance of the glue is notconsistent with 1,000-year old animal glue, whichanyway would be too weak to hold small metal parts.Most likely it is a modern polymer adhesive, although nodocumentation regarding such repairs has been found.The alloy was found to consist of 94.5% Ag and 5.5% Cu(Fig. 3 and Table 1). Also Cl and S were detected,indicating the presence of the common silver corrosionproducts AgCl and AgS. This is consistent with theblackened metal surface. No gold was detected on themetal surface. In many places natural interdendriticsurface corrosion in the eutectic reveals the micro-structure of the material (Fig. 2), alleviating the need for

surface-etching or destructive cross-section sampling.The dendritic patterns of this microstructure (Berthelon,2007) allow us to conclude that the ring was cast withoutfurther manipulation (as expected). The metal surfacefurthermore exhibits ubiquitous parallel striations(Fig. 2). These striations arguably originate from filingcarried out to remove flash and mold lines after thecasting, and the presence of file marks on the prong tops(Fig. 2) indicates that the filing took place before thestone was set (otherwise the stone would have beendamaged). Together with the absence of gold on themetal surface (i.e., the SEM-EDS results), the file marksclearly show that the previous description of the ring asgilded was mistaken: if the surface had been gilt and thegold layer had worn away, also the file markings wouldbe gone. But the metal surface displays no wear, and asthe original file marks are still in place, this ring hasnever been much used.

For the stone, SEMEDS analysis identified theelements O (70.4%), Si (20.6%), Na (3.7%), Mg (2.5%),Ca (0.8%), K (0.7%), and Al (0.7%) (Fig. S7). This is acomposition typical for soda-lime glass, even though theamount of oxygen is at the high end (this might relate tothe calibration of the table-top SEM). Examinationunder a light microscope revealed numerous sphericalair bubbles inside the stone. Such bubbles are typical formanufactured glass, but unheard of in natural crystalline

Fig 2. SEM images of details of the ring (recorded by S.W.). Upper left: Shank surface covered with file marks. Upper right: Close-up ofdendritic microstructure revealed by interdendritic corrosion, showing that the alloy was not manipulated after casting. Lower left: Filemarks are present also on the prongs, indicating that the filing was done before the stone was set. Lower right: Organic material is present inthe crevices under the stone, which is typical for archaeological objects.

Warmlander et al.: Analysis of an Arabic finger ring from Viking Age Birka, Sweden 3

materials (they might be found in e.g. amorphousvolcanic rock). We conclude that the stone is not anamethyst, as previously thought, but consists ofcoloured glass. The colouring agent(s) is unknown, asthe elements responsible for the violet hue appear to bebelow the detection limit of the employed SEMinstrument. Further elucidation of the colouring agentswould likely require destructive analysis. In differencefrom the metal, the stone displays moderate use-wear inthe form of scratches and dents. This could be inter-preted as the stone being older than the mounting perhaps the stone was reused from an older piece ofjewelry? On the other hand, the stone is the mostexposed part of a ring, and here it is made from arelatively soft material, i.e. glass with a typical Mohs

hardness of 5.56.5. It is therefore not surprising that thestone displays more wear than the silver mounting.When jewelry was inscribed in ancient times, the gem-cutters usually preferred slightly harder quartz-basedmaterials such as agate, amethyst, and onyx (King,2003; Schumann, 2011), all of which have a Mohshardness around 7. Considering that the inscription islocated on top of the stone, it is actually quite wellpreserved, which is in line with the ring body displayingminimal use-wear.

The inscription is written in a lapidary form of ArabicKufic script (Figs. 1, 4, and S2). This angular script wasdeveloped in the 7th c., dominated Arabic writing in the8th10th c., and waned in popularity during the 12th c.when it was replaced by the cursive Naskh style. In our

Fig 3. SEM-EDS spectrum for the ring surface. Data was recorded without sample-coating for five minutes at 15 kV, using a table-topHitachi TM-3000 SEM. The resulting elemental composition is shown in Table 1.

TABLE 1 Elemental composition of the ring surface, analyzed with SEM-EDS (cf. Fig. 3). The results are interpreted as a 94.5/5.5 Ag/Cualloy displaying AgS and AgCl2 corrosion. Al, Na, P, Si, and Mg are typical earth elements, and are commonly found on the surface ofarchaeologically excavated objects.Element AN Series Net unn. [wt.%] C norm. [wt.%] C Atom. [at.%] C Error [%]Silver 47 L-series 222622 81.42 84.42 63.54 2.6Chlorine 17 K-series 28205 5.96 6.18 14.15 0.2Copper 29 K-series 2187 2.79 2.89 3.70 0.1Sulfur 16 K-series 11877 2.41 2.49 6.32 0.1Aluminium 13 K-series 4283 1.22 1.27 3.81 0.1Sodium 11 K-series 1718 0.94 0.97 3.44 0.1Phosphorus 15 K-series 4183 0.92 0.95 2.50 0.1Silicon 14 K-series 1816 0.43 0.45 1.30 0.0Magnesium 12 K-series 983 0.36 0.37 1.25 0.0Total: 96.46 100.00 100.00

4 SCANNING VOL. 9999, 9999 (2015)

case, the angular style and the absence of a shidda signindicates an early version of Kufic, which is consistentwith the grave at Birka dating to around AD 850. Fromright to left, the characters appear to read AL__LL-[H?]. Considering the normal stylistic writing of theword Allah (Arabic for God) as ALLH, the last part ofthe inscription seems to invoke the Islamic high deity.That said, the elongated middle section and the extrastroke representing a third L are problematic.Presently, we interpret the inscription as ILLLH, to beread il-la-lah, i.e. For/to (the approval) of the God.Several regional variations of Arabic spelling andwriting are however known to exist, and it is furthermorepossible that the inscription was written or copied bysomeone with an incomplete understanding of Arabicwriting. Consequently, alternative interpretations of theengraving are possible. For example, if a missing line isassumed, the letters could be read as INsLLH, i.e.Inshallah (god-willing). The missing dots for N ands would then be explained by the normal conventions oflapidary Kufic. Most likely, we will never know theexact meaning behind the inscription, or where and whyit was done. For the present investigation, it is enough tonote that its Arabic/Islamic nature clearly links the ringand the stone to the cultural sphere of the Caliphate.

Discussion and Conclusions

Our analysis shows that the studied ring consists of ahigh-quality (94.5%) non-gilded silver alloy, set with astone of coloured soda-lime glass with an Arabicinscription reading some version of the word Allah.Thus, the previous description of this item as a signetring consisting of gilded silver set with an amethyst wasnot entirely correct. This raises the question whether theabsence of expensive materials in the ring (from amodern point of view) demotes its historic importanceor value? The simple answer is: not at all. Thesignificance of this ring has never been based on itspurported material composition, but on its connection tothe Islamic world. This connection is now not onlyconfirmed, but actually strengthened due to the mintcondition of the rings metal body, as will be discussedbelow.

For the stone, we must remember that even thoughcoloured glass might today be perceived as a fakematerial of lower value, this was not necessarily so in thepast. Even though glass production began around 5,000years ago in the Levant (Nicholson and Shaw, 2000;Glover et al., 2003), it was still an exotic material inViking Age Scandinavia. Judging by archaeologicalfinds from pre-historic Scandinavian workshops, itappears that the craftsmen had learned the basics ofglass-working, but did not yet master glass-production(Callmer, 77; Glover et al., 2003; Warmlander et al.,2010). Glass was consequently a prestigious materialthat had to be imported, either as ready-made objectssuch as bottles and beakers, or as rods or shatteredfragments that the local artisans could work into highlyvalued colourful beads. Even if the woman in grave 515knew that the stone in her ring was made from glass, shewould not have considered it fake.

For the ring body, the presence of original filingmarks is in stark contrast to most objects in the Birkagraves, where the standard copper-alloy jewelry almostalways displays some degree of wear. Grave goods inexpensive silver were relatively uncommon during theViking Age, and a proper use-wear study of the existingsilver jewelry still needs to be carried out. The mostcommon silver objects in the Birka grave fields arecoins, all of which were imported: the first indigenousSwedish coins were minted in A.D. 995 in the city ofSigtuna, i.e. just after Birka had been abandoned(Malmer, 2002; 2010). Many of the coins at Birkacame from the Caliphate, and had high proportions ofsilver, mainly provided by the rich silver mines inPanjshir, Afghanistan (Negmatov, 99). Such silvercoins were frequently used as raw material byScandinavian silver smiths (Kovalev, 2002; Eniosovaand Mitoyan, 2011; Boytrup et al, 2013). Given itsArabic style, the high silver content in the studied ring istherefore not unexpected. In difference from the ring,though, the Arabic silver coins that found their way toViking Age Scandinavia were usually worn and torn(Gullbekk, 2012; Hoven, 85) from passing many handsalong the established trade routes (Noonan, 89; 90;Rezakhani 2010).

When items retaining fresh production marks areencountered in excavated graves, it can be speculatedthat they were purpose-manufactured as grave offeringsby local craftsmen (cf. Trotzig, 69). In our case though,we know that the ring was produced far outsideScandinavia, and being buried in the Birka grave fieldswas hardly the main rationale behind its production. Wecan only guess what purpose the ring originally wasmeant to serve, although it was likely not intended foreveryday use. The previously suggested idea that it wasa signet ring (Arne, 14; Arbman, 40; 55; Aiken andArwidsson, 86) should probably be discarded: eventhough engraved rings were often used for such purposesin societies where most people could not read or write

Fig 4. The Arabic inscription in the stone, engraved with earlyKufic characters. From right to left it appears to read AL__LLH,which we interpret as il-la-lah, i.e. For/to Allah. CompareFigs. 1 and S2.

Warmlander et al.: Analysis of an Arabic finger ring from Viking Age Birka, Sweden 5

and where written signatures had no legal status, itwould be unusual to employ a gods name as your seal.Although harder than wax (as used in seals), glass isfurthermore not an ideal material for a signet ring,although in this case such use would be compatible withthe stone displaying much more wear than the metalbody. The lack of wear on the silver surface suggests thatthe ring passed from the Arabic silversmith who made itto the woman in grave 515 with few, if any, owners inbetween. Even though the decomposed state of thebones in the grave precludes any biochemical analysis,which otherwise could have shed light on the geographicor ethnic origin of the buried woman, it is not impossiblethat the woman herself, or someone close to her, mighthave visited - or even originate from - the Caliphate or itssurrounding regions.

Such long-distance travelling during the Viking Ageis of course mentioned both on Swedish rune stones andin Mediaeval written texts (Birkeland, 54; Androsh-chuk, 2012; Mikkelsen 2012; Montgomery, 2012;Shepard, 2012; Jonsson Hraundal, 2013;). In additionto Scandinavian expeditions to distant places, it appearsalso northernmost Europe was visited by foreigners.For example, the Hiberno-Arabic traveler Yacoubal-Tartushi has provided a lively description of theViking Age town of Hedeby, which makes it likely thathe visited at least southern Scandinavia (i.e. Jutland)(Birkeland, 54 with references; Mikkelsen, 2012).However, the ancient texts also mention encounters withgiants and dragons (as in the Icelandic Saga of Ingvar theFar-Travelled (Palsson and Edwards, 89). Thus, it is notalways easy to tell fact from fiction, especially as the oldtexts usually were written down based on hearsay. Whenbacked up by physical evidence, on the other hand,peoples stories become much more credible. By thatstandard, the importance of the studied Birka ring is thatit most eloquently corroborates ancient tales about directcontacts between Viking Age Scandinavia and theIslamic world. Such contacts must have facilitatedexchange of goods, culture, ideas, and news much moreefficiently than indirect trade involving several mer-chants in-between. The material analysis conductedhere therefore not only improves our understanding ofthe finger ring itself, but also helps to advance ourknowledge of the historic period from which it cameto us.

Acknowledgments

We thank Charlotte Hedenstierna-Jonson, GunnarAndersson, and Kent Andersson at the Swedish HistoryMuseum in Stockholm for helping us to access themuseum collections. Kjell Jansson at StockholmUniversity helped with the SEM analysis, while RomanKovalev, Sabrina B. Sholts, and an anonymous reviewerprovided helpful comments on the manuscript. Court

jeweller Christian Bolin at W.A. Bolin, Stockholm,helped with the examination of the ring and the stone.The study was financed by grants from Helge Ax:sonJohnson Foundation and Berit Wallenberg Foundationto S.W., while R.S received support from the EuropeanUnion through the European Regional DevelopmentFund (Center of Excellence CECT) and from theEuropean Social Funds Doctoral Studies and Inter-nationalisation Programme DoRa, which is carried outby Foundation Archimedes.

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Supporting Information

Additional supporting information may be found in theonline version of this article at the publishers web-site.

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