Hagia Sophia, Structures

Structure and Aesthetic at Hagia Sophia in ConstantinopleAuthor(s): Anthony CutlerSource: The Journal of Aesthetics and Art Criticism, Vol. 25, No. 1 (Autumn, 1966), pp. 27-35Published by: Wiley on behalf of The American Society for AestheticsStable URL: http://www.jstor.org/stable/428881 .Accessed: 24/04/2014 13:30

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ANTHONY CUTLER

Structure and Aesthetic at Hagia

Sophia in Constantinople

STUDIES OF THE AESTHETIC ASPECTS of Hagia Sophia1 and the principles of its design began little more than a generation ago with the pioneering work of G. A. Andreades.2 Since 1931, such inquiries have gained in sophistication although they are often marred by attempts to fit Justinian's great church into some prior notion of architectural development.3 It might appear somewhat rash to venture further opinions as the day of Van Nice's long-awaited book on Hagia Sophia draws near, especially since its author's views are based upon his many years of study and detailed measurement of the church.4 It is worth remarking, however, that this mathematical emphasis has been singularly lacking in previous investigations. The object of the present paper is to relate certain aspects of the design of Hagia Sophia to later Greek geometry. For the present, we will confine ourselves to a consideration of the pendentives and the nave capitals. These forms, and the relationship between them, derive from principles employed in the church which stands as the supreme monument to the early Byzantine sense of kinship between mathematics and aesthetics. I

The contemporary, popular distinction between the architect and builder is that

Anthony Cutler is an assistant professor of art history at Emory University. He has written articles on Byzantine art for various journals.

the former creates as much beauty as he can for the money available while the latter spends as little money as possible in the erection of a functional, and perhaps incidentally beautiful, structure. Pressed further, this estimate is based upon a belief in the differences between the architect's theoretical training in design and the builder's speedier, more practical acquisition of technical experience.

Though these concepts may be challenged both in schools of architecture and on building sites, they bear a remarkable similarity to views held in the last centuries of the Western Roman empire and the first centuries of East Rome. Downey's textual investigations5 have shown that only the vocabulary has changed. When, in the sixth century, Procopius described the principal architect of Hagia Sophia as mechanikos, he intends much more than the term mechanic suggests today. He seems to have in mind a man academically trained in areas that remove him from the mere architectus, the engineer or builder, who knew how to construct or reconstruct-the classical Greek edifices demanded by men of taste like Trajan. The mechanikos, rather, possesses a body of theoretical knowledge that enables him to "prepare in advance designs of future constructions," 6 to create something new and beautiful as a result of his training in theoretical mechanics.

Justinian demanded more of his architects than did the emperors of the second


28

century. So severely practical a structure as the Bin-bir-derek cistern involves solutions to mechanical problems unheard of by the builders of the Basilica Ulpia. And though the vast complex of buildings at Tivoli known as Hadrian's Villa7 suggests considerable technological advances upon the creations of Trajan, it is not until some time in the third century that we have evidence of that essential and manifest characteristic of early Byzantine architecture, the disciplinary relationship between mathematics and structural mechanics. About 250 A.D. the mathematician Heron of Alexandria composed his Kamarika, a treatise on vaultings now lost but which remained the foundation of Byzantine mechanics.8

The emperor continued to be officially credited as the prime entrepreneur in the construction of public, monumental works. The nymphaeum known as the Temple of Minerva Medica at Rome, the "kalybe" at Ummaz-Zaitun in the Hauran, and other North African structures preserved and developed the techniques of vaulting used in the vestibule of the Piazza d'Oro at Tivoli. Yet, despite the extensive building programs of Diocletian and Constantine, in the early fourth century Pappus of Alexandria still found it necessary, in his Synagoge, to argue the essentially mathematical basis of theoretical mechanics.9

Two hundred years later the argument is no longer to be heard. Procopius' in- valuable book on the building of Justinian insists almost as much on the mathematical preeminence of his builders as on the emperor s initiative in their creation. Anthemius of Tralles, the chief architect of Hagia Sophia, was not merely a master- builder but a geometrician of the first order. His work on conic sections and his method of constructing an ellipse have recently been translated and his treatise gives meaning to the term mechanikos.'0 The pragmatic importance of his theoretical discoveries is in ample evidence. It is the work of a man who could draw in two dimensions, construct in three, and appreciate the difference between these two modes of thought. His colleague,

ANTHONY CUTLER

Isidore of Miletus, seems to have been a professor of geometry or mechanics. Not without significance for the study of sixth century architecture is the work of one of his pupils, a supplement to Euclid that describes a method for inscribing certain regular solids in certain others and for determining the angle of inclination between faces meeting in these solids.ll We are not far from the mind that conceived the capitals of Hagia Sophia.

The architect's application of Greek mechanics is hardly to be faulted by the events of 557, when an earthquake partially collapsed the main dome twenty years after its completion. Justinian entrusted its restoration to Isidore the Younger, nephew of the first Isidore.12 The restoration has, in its fourteen hundred years, survived further earthquakes, renewed pillage, and two medieval attempts at rebuilding.

It is probable that the thrusts and stresses set in action by the unprecedented size of Anthemius' building were not pre- cisely calculable in advance.'3 However, lack of detailed information regarding the strength of materials used and their per- formance under stress must be balanced against a quite unclassical sensitivity to three-dimensional design. Early Byzantine architects seem to have possessed this quality so strikingly absent in contemporary mosaics. Thus Pappus in his Syna- goge uses the term problema to indicate a perspective illustration, a projected view drawn in two dimensions but fully sug- gesting the appearance of the finished structure. Enlargement from this view was done by quadratura, a method of squaring off. But in no way does this plane technique seem to have prevented the designer from seeing his building as a piece of solid geometry. Procopius' description of the dome of Hagia Sophia as sphairion, and sometimes hemisphairion, suggests that the historian shared some of the truly cubic comprehension of the architects whom he praises. These men, who distinguished between plan, projection, and elevation,'5 reveal themselves as fully appreciative of various three-dimensional forms and of inherent affinities between such architec-


Structure and Aesthetic at Hagia Sophia tural shapes. Nowhere at Hagia Sophia is this so apparent as in the pendentives and the capitals of the nave columns.

II

The origins of the pendentive are lost in the forest of documentation and dogma that is the principal legacy of Strzygowski16 and Rivoira.17 Much of the acerbity of the Orient oder Rom controversy cen- tered on the supposedly major supportive role of the pendentives. Partisans in the dispute sought to attribute the invention of the supremely elegant and apparently superbly functional members to some locale far east or far west of Byzantium. Had conditions in Constantinople been amenable, the energies expended in the historical battle might have been employed in archaeological surveys of the church's structure. But Ataturk opened Hagia Sophia to the world only in 1935, and we have had to wait nearly thirty years for Van Nice's demonstration that regard for aesthetics bulked as large as structural considerations in its design. It is now sus- pected that the half-domes were used "not as functional elements but purely in order to enhance the nave's spatial effect." 18

The aesthetic aspect of the interior's design was, therefore, one of the architect's priorities. In the same light, we can see the pendentives as constructs designed to fill the spaces between the arches of the nave. Their primary function is to effect a palpable transition between the circular plan of the dome and the square formed by the four central piers. A mobile, not a static, eye is required to appreciate this transition. Byzantine descriptions of the church19 demand a gaze that travels over the decorations rather than a motionless concentration on one particular figure or feature.

The pendentive is just such a decorative feature, a mass of brick shaped in the mind and set in place by the builder. It is material substance and therefore, like all matter, intended to be moulded by man for his own purposes. This understanding is at the root of Byzantine admiration for

29 technical innovation in architecture: matter is malleable and when one mind has given it form, another can appreciate that formulation.20 The shaped form is, in short, aisthetos-that is, perceptible to the senses.

The treatise of Anthemius, cited above, suggests that applied geometry is a means of fashioning the material world. His search for the center of gravity in a cylin- drical column implies the role that mathematical and mechanical theory play in the pragmatic equipment of the architect. In such experiments Anthemius writes as the heir not only of Heron and Pappus but also of Proclus. The commentaries on Euclid of this fifth century geometer in- clude the suggestion that a cylinder be considered not as a cylinder but as a pit.2' Anthemius himself tells us that "research into such matters belongs fittingly and thoroughly to him who would be called the son of the Muses." 22

The same analogical sense of volumes is to be found in Hagia Sophia. Architec- tural forms are by definition not two- dimensional, linear compositions but masses occupying space. Large or small, by means of their form, they affect our appreciation of adjacent masses. The galleries give a sense of scale to the church, human in proportion to the broad span of the arches and the seemingly titanic vaults. The half-domes prepare the way and (as Van Nice has shown) enhance the effect of the crowning hemispheres. And the pendentives have an almost syntactical importance in relating arch, dome, and gallery (P1. 1). Their mosaic sheathings perform as connective tissue between other surfaces. They begin at the perimeter of the great dome and by their curving contours guide the eye to the main piers some eight stories above the pavement.

From this point down, from the second cornice to the first and from the first cornice to the pavement, the scale is sug- gested by the colonnades. A man can stand in the nave and comprehend the height of the structure by measuring himself against the four columns that separate the nave from the aisle. Above these columns, at


Plate 2

Plate 1

z

C

H

o z

n c

r M


Structure and Aesthetic at Hagia Sophia triforium level, are six further monolithic cylinders. Together they form superim- posed column-screens which break up into perceptible units the colossal inter- vals between the principal structural elements of the church. Longitudinally, the columns define the distance between the main piers. Vertically, they parallel those piers yet divide their immense height into more readily apprehensible com- ponents.

In this complex of functions, the columns resemble the pendentives. These divide the circumference of the dome into quadrants and thus direct the eye horizon- tally. At the same time they vertically diminish towards the point where the arches spring from the main piers. But it is in their function in the third dimen- sion that the pendentives can be seen as the most subtle expressions of the Byzan- tine sense of volume. Their concave form extends the hollow space under the great dome yet seems to anchor the vault super- structure at its imposts. The shallow voids created by the pendentives ease the tension of that canopy stretched across a hundred feet of space. They reduce the circumference first by extending it, ultimately by securing it four-square at the crossing. Functioning in height, width, and depth, the pendentives not only solve the theoretical and physical problem of squaring the circle. They resolve the aesthetic and metaphysical dilemma of connecting the uppermost, celestial regions of the church with the galleries, those parts where humanity could walk.

III

In terms of the main structural system of Hagia Sophia, the colonnades of the nave, galleries, and exedrae play as little part in load-bearing as do the pendentives. Their main function is to transmit to the foundations the thrust of their adjacent vaults. But beyond this purely structural purpose they perform as aesthetic elements. The column-screens define the nave without rigidly confining it. Their archi- volts repeat the decorative, semi-circular motif of the arches and the tympanum

31

walls. And, in their capitals, they express the lateral and vertical thrusts of the local load that they bear.

The form of their capitals is the result of what seems to have been felt needs in both mechanics and aesthetics. On the one hand, their truncated and inverted pyramidal form successfully reconciles the base of the archivolt with the column. The square plan at the impost where abutting arches meet is reduced by means of splay- ing the sides of the capital and chamfer- ing its angles to produce a circle at the astragal (Figs. 1 and 2). On the other hand, this very reduction seems to direct the lateral thrusts of the abutting arches down the vertical cylinder of the column. The complex of forces acting upon the capital is thus contained by its appropriate shape and conducted in the required direction.

Any estimate of the degree to which this mechanical disposition is successful -and about the complementary role of the tie-rods in the gallery colonnades- must wait upon the publication of Van Nice's researches. On formal grounds the shape of the capital is impeccable. Not only does it provide a suitable seating for the masonry burden that it helps to carry. It works a metamorphosis upon the shape of this burden, gradually converting its square form at the impost to the circle that is a horizontal section of the shaft below.

It is now apparent that this achieve- ment is a smaller restatement of the transition effected by the pendentive.23 The latter's concave triangle is, in essence, an inversion of the capital's convex form. Seen in geometric terms, it appears that the shapes enclosed by the main arches of Hagia Sophia correspond directly to the splayed sides of its capitals, while the pendentives' form answers directly to that of the capitals' chamfered angles (Fig. 3). This affinity could hardly have been mnissed by the architect designing his structure in terms of three-dimensional problemr ta.24

For the worshiper standing in one of the side aisles, the view upwards towards the great dome is dominated by the capitals of the nave columns silhouetted against the shape of the pendentive; the almost


z H

o z

0 c 3^ Plate 4 Plate 3


Structure and Aesthetic at Hagia Sophia instinctive search for the crowning feature of the church projects the lesser resolu- tion of the square-and-circle problem against the greater exposition of the same solution. This relationship between pendentive and capital probably escaped that large portion of the congregation whose minds were not attuned to the subtleties of later Greek geometry; indeed, it has evaded the attention of modern writers on the Great Church. It is, nonetheless, evi- dent that the contour of the pendentive leads from the circular plan of the dome to the square established by the four main piers, while that of the capital leads the eye from the square plan of the abacus down to the circumference of the shaft.

That the capitals of Hagia Sophia were meant to be seen in this fashion is sug- gested by the difference between them and capitals in contemporary structures. At Hagia Sophia, the verticality of the column is not interrupted, as it is at San Vitale, by a dosseret block (P1. 3). In the church at Ravenna, there was no need to clarify the shape of the capitals in this way for there was no manifest aesthetic relationship between their form and that of the squinches in the octagonal drum (P1. 2). At Hagia Sophia, however, the eye perceives the rela- tively small statement of the capital made against the massive, spherical triangle of the pendentive. And the geometrical con- gruity between the two shapes is not fortui- tous. It stems from an understanding that both members, the immense pendentive and the comparatively slight capital, perform the same aesthetic function. Analo- gous shapes, they each effect the most satis- factory junction between square and circle.25

The means by which this linkage is made can be well seen in the Bin-bir-derek cistern, a product of the same period of building activity as the Great Church. In the cistern, the transition from shaft to vault by means of the splayed-and-chamfered member can be seen without the celebrated basket-work of the capitals in Hagia Sophia. This adornment, however, is much more than a decorative after- thought. Rather than disguise the solution

33

FIG. 1

FIG. 2

FIG. 3

discovered by Anthemius, the basket relief rehearses the transition from the square to the circle (P1. 4). But it transposes the connection from the area of mathematics to the realm of nature. While there is considerable individual variation between nave capitals, a general aesthetic principal can be detected. Main stems of acanthus rise vertically from the astragal only to branch into tendrils moving in the horizontal plane around the surface of the block. The geometric manner in which the hard edge of the echinus has been reduced is disguised by the foliage; the organic growth connects what otherwise


34

would be four distinct aspects of the capital. In this way, the vegetable sculpture accentuates both the circularity of the column and the horizontal progress of the archivolt. This aesthetic emphasis gains further strength from its repetition at the triforium level.

Thus the formal essence of the capital's shape is restated in organic terms that comprehend even the volutes in the intri- cate growth of natural forms. The sculp- tors of the capitals in the nave and the exedrae (though not in the galleries) took further pains lest the vegetable relief obscure the truncated pyramid that was these capitals' geometric origin. The volutes are placed at the top of the echinus where they fill an area almost as wide as that of abacus above them. In contrast, the volutes on capitals in a church such as Hagia Sophia at Salonika (c. 495) are placed below the echinus and only a little above the astragal.27 There they inter- rupt the smooth diminution of the inverted pyramid and conceal the chamfered angles that aesthetically ease the square above into the circle below. At Hagia Sophia in Constantinople, such interfer- ence is designedly avoided.

Much else remains to be said about the relationship between the pendentives, the nave capitals, and other features of the Great Church. Gervase Mathew has ob- served that "the whole of Hagia Sophia, decorations as much as structure, is an application of geometry to solid matter."28 Unfortunately his Byzantine Aesthetics, searching as it is on the mathematical background, deals only cursorily with architecture. Now that Van Nice's work draws near to publication, the historian will be in a position to understand better the complexities of Anthemius' structural system. But, more important, he will possess a solid basis in fact, a detailed ac- count of Byzantine geometry in the supreme example of its application. For the first time it will be possible to appreciate what architectural aesthetic meant to the medieval Greek, an epithet for material substance formed and understood in the light of the spirit.

ANTHONY CUTLER

1I am grateful to the British Council for a grant which, among other things, enabled me to study Byzantine architecture in Turkey and Yugoslavia. Preliminary work on this paper was done by Mr. Wayne Moulton, a research student working under my direction at Emory University.

2"Die Sophienkathedrale von Konstantinopel," Kunstwis. Forsch., I (1931), 33-94.

'E. g. H. Sedlmayr, "Das erste mittelalterliche Architektursystem," Kunstwis. Forsch., II (1933), 25-62; idem., "Zur Geschichte des justinianischen Architektursystems," Byz. Zeitschr., XXXV (1933), 38-69. Although the title of his book implies such a historical viewpoint, W. R. Zaloziecky, Die Sophienkirche in Konstantinopel und ihre Stellung in der Geschichte der abendldiindischen Architektur (Rome and Freiburg-im-Breisgau, 1936), is a much more objective treatment. Of many other important studies, mention must be made of W. L. Emerson and R. L. Van Nice "Hagia Sophia, Istanbul," American Journal of Archaeology, XLVII (1943), 402-436, and W. L. MacDonald, "Design and Tech- nology in Hagia Sophia," Perspecta, IV (1957), 20-27. A useful appreciation of aesthetic considerations of Hagia Sophia before the Second World War is to be found in E. H. Swift, Hagia Sophia (Morningside Heights, N. Y., 1940), pp. 30-49. At the time of writing, I had not seen the interesting essay by P. A. Michelis, L'Esthetique d'Haghia-Sophia (Faenza, 1963).

4By way of an interim report, see R. Van Nice, "The Structure of Hagia Sophia," Architectural Forum (May, 1949), pp. 131-138, 210.

6 G. Downey, "Byzantine Architects. Their Train- ing and Methods," Byzantion, XVIII (1948), 99-118.

6 De aed., Loeb ed., I, I, 24. 7The most recent study is S. Aurigemma, Villa

Adriana (Rome, 1962). 8 Sir Thomas Heath, A History of Greek Mathe-

matics (Oxford, 1921), II, 306-310. 9 Downey, p. 106. 10G. L. Huxley, Anthemius of Tralles, a Study

in Later Greek Geometry (Cambridge, Mass., 1959). For a discussion of Anthemius' mechanical experiments, see p. 29.

"Downey,p. 113. 12 The rebuilt dome was increased in height so

as to bring the thrusts more vertically upon the main piers, Emerson and Van Nice, "Hagia Sophia, Istanbul," p. 404.

13 Van Nice, "Structure," p. 132. 1The disparity between the methods of the

painter and those of the architect suggests that the latter enjoyed training in the geometry of solids while his colleague in the figurative arts did not. Unfortunately we lack any document on the training of Greek Christian painters before the eight- eenth century.

"Downey, pp. 114-117. 10See especially his Origins of Christian Church

Art, trans. 0. M. Dalton, H. M. Braunholtz (Oxford, 1923). For an appraisal of his work, E. Herzfeld, W. Koehler, C. R. Morey, "Josef Strzygowski," Speculum, XVII (1942), 460-461.


Structure and Aesthetic at Hagia Sophia 17Lombardic Architecture, Its Origins, Develop-

ment and Derivatives, trans. G. McN. Rushforth (New York, 1910).

18 "Structure," p. 210. In a recent amendment to his earlier views, "St. Sophia's Structure," Archi- tectural Forum (Aug.-Sept., 1964), pp. 45-49, Van Nice returns to the belief that the half-domes exert considerable inward pressure on the upper parts of the transverse arches against which they abut. In doing so, of course, they buttress the main dome. This revised estimate in no way detracts from the probability that the entire design of the nave was so structured as to leave it as uncluttered as possible.

19 These ekphraseis persist from the sixth century to the fourteenth and constitute an important genre in Byzantine literature. The most celebrated is Paulus Silentiarius' verse description of Hagia Sophia, Migne, Patrologia Graeca, LXXXVIb (Paris, 1865), cols. 2119-2158.

35

20G. Mathew, Byzantine Aesthetics (New York, 1963), p. 24.

21 In Euclideln, I, 8-12. 23 Huxley, p. 25. 23 See above. 24 The suggestion of a close theoretical relation-

ship between the design of the capitals and the pendentives at Hagia Sophia has an obvious bearing upon the problem of the historical origins of these forms. However, it is not our intention to write a postscript to the Orient oder Rom controversy.

25Swift, Hagia Sophia, p. 40, seems to have appreciated this aspect of the pendentives which "function as abstract geometrical forms realized in some thin, light material."

20 For the sculpture of the nave capitals see A. Grabar, Sculptures byzantines de Constantinople, IVe-Xe siecle (Istanbul-Paris, 1963).

27 Rivoira, Lombardic Architecture, p. 64, fig. 92. 28 Byzantine Aesthetics, p. 67.


Article Contentsp. [27]p. 28p. 29p. 30p. 31p. 32p. 33p. 34p. 35

Issue Table of ContentsThe Journal of Aesthetics and Art Criticism, Vol. 25, No. 1 (Autumn, 1966), pp. 1-120Front Matter [pp. 1-2]Inside and Outside in Architecture: A Symposium [pp. 3-15]Problems of Artistic Form: The Concept of Form [pp. 17-26]Structure and Aesthetic at Hagia Sophia in Constantinople [pp. 27-35]The Practical Aesthetics of Thomas Busby's Music Reviews [pp. 37-45]Polarity and Atonalism [pp. 47-52]Principles of Opposition and Vitality in Fang Aesthetics [pp. 53-64]Panthea: Lucian and Ideal Beauty [pp. 65-70]Samuel Johnson's Principles of Criticism and Imlac's "Dissertation upon Poetry" [pp. 71-82]Formal Specification [pp. 83-88]Attitude and Object: Aldrich on the Aesthetic [pp. 89-91]The Art of Blotting [pp. 93-103]ReviewsReview: untitled [p. 105]Review: untitled [pp. 105-107]Review: untitled [pp. 107-109]Review: untitled [pp. 109-111]Review: untitled [p. 111]Review: untitled [pp. 111-112]Review: untitled [pp. 112-113]Review: untitled [pp. 113-114]

Books Received [pp. 115-116]Notes and News [pp. 117-118]International News and Correspondence [pp. 119-120]Back Matter

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Hagia Sophia, Structures