The Christian East
The early Byzantine period (330–726)
When Constantine began to build his new capital on the Bosporus, a mass of artisans was assembled for the purpose. The majority of them were drawn from Rome, so that, at first, official art was early Christian in style and was, in fact, virtually Roman art: the Classical basilica was adopted as the usual type of Christian church; portrait statues of emperors were set up as in pagan times, and sarcophagi were elaborately sculptured; floor mosaics of Classical character were widely used; and works in ivory and metal retained a basically Roman character. Change was in the air, however, even before the capital had been moved from Rome. In architecture the post-and-lintel style in stone, which had been taken over from the Greeks, was already giving place to an architecture of arches, vaults, and domes in brick, whereas sculptural ornament was becoming more formal and less naturalistic. These changes were accelerated at Constantinople partly because of the proximity of the city to Asia Minor and Syria, both fertile centres of new artistic ideas that had developed independently of Rome. Indeed, church architecture in those areas progressed considerably between the 4th and the 6th centuries, while in the visual arts a style that favoured formality and expression rather than the idealized naturalism of Classical art had begun to find approval at an early date.
Constantine’s new capital was carefully laid out and boasted an important series of secular buildings—walls, hippodrome, forums, public buildings, arcaded streets, and an imperial palace—all of great magnificence. The religious structures he set up were of two principal types: longitudinal basilicas and centralized churches. The former, usually with three aisles, were intended for congregational worship; the latter, which were circular, square, or even octagonal, were for burial or commemorative usage. Both types were to be found over a very wide area, though there were, of course, numerous local variations. It was through a subtle combination of the two types that the characteristic church of the Byzantine Empire emerged, thanks to some experiments made in the eastern Mediterranean area in the 5th century. The progress cannot be followed exactly because so much has been destroyed, but the earliest surviving church in Constantinople, that of St. John of Studium (Mosque of İmrahor), shows that this process had already gone quite far by the year it was built, 463. It is a basilica in that it has an eastern apse and three aisles, but in plan it approaches a centralized building, for it is nearly square, in contrast to the long basilicas in vogue in Rome. A similar change characterizes the sculptures that adorn its facade, for they are in low relief, in contrast with typical Roman high-relief sculpture, and the motifs are treated formally, as pieces of pattern, rather than as depictions of natural forms.
The process of development that began in such examples had greatly advanced by the end of the century, as recently discovered remains of the church of St. Polyeuktos show. The church was founded by the princess Juliana Anicia (granddaughter of Valentinian III), whose name is known from an illuminated manuscript dated 512. The change was advanced still further some 30 years later, thanks to the patronage of the emperor Justinian, one of the greatest builders of all time. He was responsible for four major churches in Constantinople: Saints Sergius and Bacchus, a centralized building; the church of St. Eirene (Irene), a basilica roofed by two domes in echelon (i.e., parallel-stepped arrangement); the church of the Holy Apostles, which was cruciform, with a dome at the crossing and another on each of the arms of the cross; and, finally, the great cathedral of Hagia Sophia, where the ideas of longitudinal basilica and centralized building were combined in a wholly original manner. The distinctive feature of all these structures was the form of roof, the dome. In Saints Sergius and Bacchus it stood on an octagonal base, so that no great problems were involved in converting the angular ground plan to a circle on which the dome could rest. But in the others the dome stands above a square, and the transition from the one to the other was complicated. Two separate processes of doing this had evolved: the squinch, a niche or arch in the corner of the square, which transformed it into an octagon, over which the dome could be placed without great difficulty; and the pendentive, a spherical triangle fitted into the corners of the square, its vertical sides corresponding to the curves of the arches supporting the dome and its upper side corresponding to the circular base of the drum. This served to brace and support the weight and to transfer it downward to the ground at the same time. The squinch served its purpose well enough and continued in use for many centuries, but it had certain weaknesses; the pendentive was one of the great architectural inventions of all time, transforming what had been mere building, where stress was counteracted by mass, into organic architecture, where thrust was compensated by thrust and strength depended on balance. So far as is known, the squinch was first used in Persia and the pendentive in Syria.
Though Justinian’s domed basilicas are the models from which Byzantine architecture developed, Hagia Sophia remained unique, and no attempt was thereafter made by Byzantine builders to emulate it. In plan it is almost square, but looked at from within, it appears to be rectangular, for there is a great semidome at east and west above that prolongs the effect of the roof, while on the ground there are three aisles, separated by columns with galleries above. At either end, however, great piers rise up through the galleries to support the dome. Above the galleries are curtain walls (non-load-bearing exterior walls) at either side, pierced by windows, and there are more windows at the base of the dome. The columns are of finest marble, selected for their colour and variety, while the lower parts of the walls are covered with marble slabs. Like the elaborately carved cornices and capitals, these survive, but the rest of the original decoration, including most of the mosaics that adorned the upper parts of the walls and the roof, have perished. They were all described in the most glowing terms by early writers. But enough does survive to warrant the inclusion of Hagia Sophia in the list of the world’s greatest buildings. It was built as the result of the destruction in a riot of its predecessor, the basilica begun by Constantine, and the work of rebuilding was completed in the amazingly short period of five years, 10 months, and four days, under the direction of two architects from Asia Minor, Anthemius of Tralles and Isidorus of Miletus, in the year 537.
From the little known it would seem that similar changes were taking place in secular architecture. The walls of the city, which still in greater part survive, were set up under Theodosius II (408–450) early in the 5th century, and already the method of construction (where a number of courses of brick alternate with those of stone) and the forms of vaulting used to support the floors in the numerous towers show several innovations. The walls themselves, a triple line of defense, with 192 towers at alternate intervals in the inner and middle wall, were far in advance of anything erected previously; they were, indeed, so well conceived that they served to protect the city against every assault until the Turks, supported by cannon, attacked with vastly superior odds in 1453. Also distinctive were the underground cisterns, of which more than 30 are known in Constantinople today. They all took on the same character, with strong outer walls and roofs of small domes supported on tall columns. Some are of great size, some comparatively small. In some, like the great Basilica Cistern near Hagia Sophia called by the Turks the Yerebatan (Underground) Palace, old material was reused; in others, like the even more impressive Binbirdirek (Thousand and One Columns) cistern, new columns of unusually tall and slender proportions and new capitals of cubic form were designed specially. These cisterns assured an adequate supply of water even when the aqueducts that fed the city were cut by an attacking enemy. Many of them were still in use at the end of the 19th century. Contemporary texts show that the houses were often large and elaborate and had at least two stories, while the imperial palace was built on enormous terraces of masonry on the slopes bordering the upper shores of the Sea of Marmara. The palace was founded by Constantine, but practically every subsequent emperor added to it, and it eventually became a vast conglomeration of buildings extending over more than 100 acres (40 hectares). Many of the buildings were of a very original character, if the descriptions that survive are to be believed; unfortunately, nearly all have been destroyed in the course of time.