In Hagia Sophia and the Byzantine Aesthetic Experience, Nadine Schibille has given us a fascinating new angle with which to think about Byzantium's most famous architectural enterprise. Justinian's Great Church, constructed in the remarkably short timespan of five years and ten months (532-537), forever changed the landscape of what was achievable in constructing and decorating a Christian building. Indeed its mind-numbing size, extravagant mosaics, stunning marble sheathing, sculpture and of course its daring structure rendered it immediately and rightfully famous, as it still is today. Everyone who studies late antiquity and Byzantium is familiar with it, yet in many ways we barely know this building. While older monographs typically addressed the church in its entirety, recent studies have tended to delve into the details. It seems that the difficulty of studying the monument nowadays (accessibility, contested status, permissions), together with its overwhelming size and reputation, demand that we attack it in smaller, bite-size pieces.
So it is that Schibille examines the church of Hagia Sophia in terms of its natural illumination, that is, the daylight that poured in through its numerous arched, glazed windows. The author is particularly invested in how this natural light affected the sixth-century mosaic program on the walls and ceilings overhead and how viewers were affected by and responded to the colorful tesserae and scintillating cubes of gold and silver sandwiched between glass and canted to reflect the radiant light from outside. (The artificial light within the building is not discussed in detail.) This may not sound like a large project, but it is. Schibille not only deciphers underlying meanings in the famous aniconic mosaics; she examines how illumination may have been appreciated and discussed by intellectuals in late antiquity and how these philosophical discussions perhaps influenced the decorative program of the church. This ultimately sets the stage for a lengthy discussion of the question of sixth-century aesthetics as they pertain to this and other late antique monuments commissioned by Justinian. Featured are, in addition to the Hagia Sophia, the churches of St. Catherine on Mount Sinai (548-65, with attention to the Transfiguration mosaic) and the bema mosaics in San Vitale in Ravenna (dedicated 547). The decorative programs of these famous monuments are evaluated, compared and contrasted, and finally discussed in terms of their possible interpretations and the underlying aesthetic principles they may incorporate. Schibille is especially interested in Neoplatonic philosophy. Readers should know at the outset that this is a book for those with a specialized interest in aesthetics, and that in some ways it relies more on the philosophy of art and late antique notions of beauty than on the pragmatic nature of art and architecture that the work is purportedly about.
The book is structured into seven chapters, of which the first four are devoted largely to monuments, mosaic programs and the important oral performances: the well-known ekphraseis of Procopius and Paul the Silentiary together with an anonymous kontakion (hymn) ostensibly intended to satisfy the masses. Schibille begins (Chapter 1) with these, since they presumably negotiated the spectacle for a viewing/hearing public when the building was twice inaugurated: first in 537 and again in 558 following a collapse of the great dome and its subsequent rebuilding. She connects these performative moments to the notion of spiritual transformation as well as a kind of "educational experience" in how late antique viewers were expected to relate to this grandiose, over-the-top monument, here relying on the bounty of modern-day literary analyses that have been devoted to these surviving poetic accounts. It is through these, especially, that we are to understand the religious/philosophical implications of the Hagia Sophia as Divine Wisdom wherein sensible light is associated with divine illumination and cognition, a theme carried throughout the book. According to Schibille it is the more explicitly theological inauguration kontakion through which the building becomes something more: "the dwelling place of the divine," "a sanctuary of wisdom" (37). The kontakion is the popular counterpart for the masses but also, for the author, it provides a spiritual and experiential way of understanding natural light specifically as divine presence within the building where it offers an epiphanic viewing experience for beholders (41).
Schibille turns to the architecture of the building in Chapter 2. She holds that natural light was an essential design component underlying the church's form and construction. She challenges the old idea of a hierarchy of light that is often proposed for the church, wherein the building ascends from darkness (aisles, narthex, i.e., the earth) toward the upper, light-filled reaches of the building (the dome and heaven). She holds instead that the primary goal was to create even, non-directional illumination that united the interior space and complemented the program of artificial light inside, thereby creating a clear expression of the underlying aesthetics of divine wisdom/divine light. Schibille utilizes here the interior (virtual) reconstructions of Hagia Sophia created by a team from the Technische Universität Darmstadt, and they are beautiful (Illustrations 2 and 3 in the plates). To what extent we can trust these experimental models, however, remains unclear, and one suspects that the deep aisles were actually quite dark, even without the external additions to the building that render it so today. And of course there is the inevitable event of use and modification by human beings, even as early as late antiquity if we are to believe what we see in the Theodora panel in Ravenna. We should probably expect partitions, furniture, makeshift rooms and especially the use of curtains, for which we have clear evidence, both literary and physical, in the case of the Hagia Sophia.  Anything is possible, and all of it impossible to predict.
The author is on surer footing when it comes to window glass and glass tesserae (Chapters 2 and 3)--her area of expertise. Woven in to this section is a brief discussion concerning the technology of glass tesserae, much of which is relegated to the notes. One would like more here. She contends that the glass panes of the building were likely translucent, though evidence is sparing. Her conclusion rests on a mere suspicion that the Byzantines preferred natural light (68) via translucent or faintly colored glass rather than, say, alabaster, but firm evidence is lacking. Hidden away in the notes is a brief sentence about the sorts of materials that, in a pinch, could substitute for a good glass panel, including parchment, horn, fish bladders, and stomachs of cattle! (68 n.104). This kind of detail is not only fun and interesting but sets the imagination running full-throttle and aching for more. Here we also learn that light as it was filtered through fifth to seventh-century window glass seems to have been virtually colorless, with just a tinge of yellow (Schibille compares it to sunlight) and, intriguingly, that the light within Hagia Sophia may be related to the colors and materials of its interior decoration so that blue and silver tesserae, for example, may intentionally receive less light than the more reflective gold and red tesserae (69). This may or may not be true. Light is tricky: It is ever-changing and, above all, subjective when it comes to humans and our perceptions of color. We are not provided with any data or evidence (here or elsewhere in the book) that supports these assumptions. One would like to know more about the author's study of the building, the windows, and the effects of light, presumably in situ as she found them. So while the hypotheses may be interesting, they leave us, in the end, with little to go on.
Chapters 3 and 4 are largely devoted to the building's interior decoration, beginning with the marble pavements. This seems to take the reader off track and does not depart from content that has been discussed at length by others.  The notion of a "puritanical aniconism" in the book-matched marble panels is interesting but feels like a reach; more likely is the tendency to show off--a demonstration of power, in the grand fashion of Roman emperors, by a ruler who can bring deluxe, multi-colored marbles from anywhere he wishes within his vast dominion. But it is the mosaics that take center stage, and here again we are guided by the author's sound knowledge and extensive experience working with glass and mosaic as she takes us on a journey through the building to expose the possibilities of this medium in terms of overall design principles, content, impression and meaning. Her emphasis is on what she sees as a prevailing theme of light and dark contrasts (chiaroscuro) paired with simple "line drawings," that is, the clear and pared-down motifs and symbols executed with a minimal palette of gold, silver, red, blue and green (110). She understands the mosaics to serve as "a vehicle of light rather than providing any exclusive visual focus" (111), a matter that has repercussions for the final chapters of the book treating with aesthetics and Neoplatonic philosophy. A discussion of color theory as it pertains to the "classical idea of primary that is pure and unmixed colours" (119, sic) is confusing and seems not fully developed. Hidden meanings are detected in color: deepest blue is "divine darkness," for example (153). More interesting is her contention that the simple "line drawings and monochromatic designs on walls and vaults emphasize the two-dimensionality of reflective surfaces" (121). This runs contrary to how we typically think about, and teach, the Hagia Sophia--as a building that defies logic and understanding through a decorative program that dematerializes walls and vaults and creates an aura of wonder and mystery. Schibille's consideration of the decorative program as a testament to the "solidity and unity of the architectural structure underneath" (121) turns a very old chestnut on its head and gives us, perhaps, something new to chew on.
The final three chapters treat the concept of beauty and what Schibille considers as the function of art in the sixth century. The focus is primarily on Pseudo-Dionysus, who identifies beauty with the good (the Platonic ideal) in that it has the ability to raise one's mind "from the material to the immaterial divine" (176). Light symbolism is pervasive here, and of course the Hagia Sophia's luminous interior is understood as a genuinely symbolic space and even, according to the kontakion, "God's chosen dwelling place" (190). Contemplation of beautiful objects or a luminous building can thus become a pathway to god through an aesthetic experience. This precipitates Abbot Suger's fixation with Pseudo-Dionysus and light-filled spaces at St. Denis by some 600 years, but the sentiments are more or less the same. As the author reminds us, for the pre-modern viewer, sumptuous works of art and architecture had profound agency, offering even a path to God by way of profound aesthetic experience.
The book has a number of problems, most noticeably repetition. Points are driven long and hard, and the reader encounters the same argument at least three times within each chapter (beginning, middle and end), and then once more as a start-up to the following chapter. A number of infelicitous spellings (transverse instead of traverse; Barasanti rather than Barsanti; henads instead of enneads, etc.) were also missed. Readers who want to understand the locations of the non-figural mosaics should have at the ready a copy of Mainstone's Hagia Sophia, Architecture, Structure and Liturgy of Justinian's Great Church (plate A11). A small version of this would have been an asset to the book in order to visualize the location of the mosaics within the building. This aside, Nadine Schibille has given us much to think about regarding the church of Hagia Sophia, its splendid mosaics, their potential interpretations and the late antique viewers who first attempted to decode their potential meanings.
1. H. Kähler, Hagia Sophia (Praeger Publishers, 1967), images 22, 23.
2. B. Pentcheva, "Hagia Sophia and Multisensory Aesthetics," Gesta vol. 50 no. 2 (2011), 93-111; W. Lethaby, "Pavements like the Sea," in Architecture, Meaning and Myth (1892), 201-210.