Architecture in the First Golden Age
During the First Golden Age, architecture continued to use the basilican plan with its plain timber roof and colonnades dividing the nave from the side aisles. Examples such as Sant'Apollinare in Classe (534–538) and Sant'Apollinare Nuovo (about 500), both in Ravenna, also make use of the typically Byzantine dosseret, a block above the capital that supports the arches and concentrates their weight on the capitals. The first clear structural example of the use of the dosseret is in the Basilica Ursiana (370–384), Ravenna, an otherwise Roman building. The dosserets, coupled with the spiny acanthus motif in the capitals and the gorgeous mosaics, give to the Ravenna churches a decidedly Byzantine flavor.
Even more Byzantine in style is San Vitale, Ravenna, which was completed by Justinian in 547. The central dome rests on squinches, with columnar niches between seven of the eight piers and a vaulted chancel in the eighth. An octagonal aisle surrounds this complex. Windows in the drum light the central area. Colored marbles, mosaics, and the surface carving of the capitals and dosserets are purely Byzantine. Charlemagne's chapel (796–804) at Aachen (Aix-la-Chapelle) is a much simpler and somewhat naïve restudy of this church, but it lacks entirely the polychromy of its model.
Similar in plan to San Vitale is the Church of Saints Sergius and Bacchus (527–536), Constantinople. An octagon of piers and arches supports a dome whose shape is gored like the rind of a cantaloupe—a form that had a precedent in the Villa of Hadrian. The interior has been so modified as to obscure its Byzantine richness.
Hagia Eirene (St. Irene), Constantinople, which was rebuilt under Justinian but greatly altered since, has two domes over the nave—a hemispherical one with a row of windows around its base, and an elliptical one to the west of that. Thus domical forms were made to cover a longitudinal nave.
The masterpiece of Byzantine architecture of the First Golden Age is Hagia Sophia (meaning "Divine Wisdom"; also called St. Sophia), in Constantinople. It was built under the patronage of Justinian, who, when the older basilican church was burned during the Nika Insurrection in 532, commissioned Anthemius of Tralles and Isidorus of Miletus to build a new church. It was completed in 537. It is almost certain that Anthemius had visited his brother, a noted physician in Rome, and there had mastered the principles of Roman architecture. Anthemius' dome for Hagia Sophia fell after an earthquake in 558, but by 563 it had been replaced substantially in its present form by the younger Isidorus.
Hagia Sophia was preceded by an open court, or atrium, and entered through a double narthex, or vestibule. The church itself measures 308 feet by 236 feet (94 meters by 72 meters). The principal feature of Hagia Sophia, its dome, is about 102 feet (31 meters) in diameter. Such a vault presses outward in all directions, requiring massive support, which is provided in this case by broad arches to the north and south. Four huge piers, themselves buttressed by masses of masonry outside the building, hold the pendentives. Half-domes to the east and west, almost as large as the main dome, extend the length of the nave and help to abut the main dome. These, in turn, are abutted by smaller half-domes over columnar niches. Colonnades between the piers separate the aisles and the galleries over them from the nave.
The Byzantine architects, following the precedent of early Christian basilicas, left the exterior with little or no decoration. However, the structural system of Hagia Sophia itself gives monumentality to the exterior of the building. The system of vaults, niches, buttresses, and half-domes leads up like waves to culminate in the main dome. Blocks of masonry between the windows of the dome weight its base like so many buttresses, leaving only the upper part of the dome's curve apparent from the outside.
The builders of Hagia Sophia lavished their efforts on the interior of the building. Few churches were better lighted; great lunette windows pierce the curtain walls over the galleries to the north and south. Windows around the base of the dome flood it and the area below with light, visually reducing the solid appearance of the supports between the windows and creating the effect of a weightless dome suspended from above instead of supported from below.
To this lightened impression the color scheme is ancillary. Red porphyry and verd antique marble form the columns, while the walls up to the level of the capitals are sheathed in slabs of polychromed veined marble, cut so that the pattern of the veining is reversed in consecutive slabs. Dark blue color applied to the interstices of the patterns carved in capitals and moldings emphasizes the surface decoration by contrast to the white marble. These capitals adhere to none of the traditional orders of Roman architecture but are free designs of a cushion or basketlike shape. They may borrow the convex curve of the Doric echinus, the scroll forms of the Ionic, and the leafage of the Corinthian order (now become the conventionalized spiny acanthus), but all are fused into something new and distinctly Byzantine. Above the level of the columns, the walls, arches, and vaults glitter with gold mosaic, carried around even the edges of intersecting planes. Small wonder then that Justinian prided himself on the building he had erected, and well might he exclaim, "I have surpassed thee, O Solomon!"
After the capture of Constantinople in 1453 by the Ottoman Turks, Hagia Sophia was converted into a mosque. Some of its exterior surfaces were banded alternately light and dark, and four minarets were added at the corners. Hagia Sophia is now a museum.