The churches of Saints Sergius and Bacchus,…
December 537 CE
The churches of Saints Sergius and Bacchus, constructed in Constantinople between 527 and 536, exemplify the centralized plans beginning to be used for congregational churches as well as for martyrs’ shrines, probably because of the growing importance of the cult of relics.
Meanwhile, architects and builders have worked apace to complete the new Church of the Holy Wisdom, Hagia Sophia, designed to replace an older church destroyed in the course of the Nika revolt.
In five years, they have constructed the edifice (which stands today as one of the major monuments of architectural history).
The daring engineering and structurally innovative design for the immense new Great Church, with its shallow but colossal central dome resting on four huge arches buttressed by two half domes, is developed by the scholars Anthemius of Tralles and Isidorus of Miletos.
Anthemius, although neither architect nor master mason by training, has written a treatise on the geometry of conical sections, possesses knowledge of projective geometry, and is conversant with the mechanical inventions of Archimedes.
The extraordinarily magnificent Church of Hagia Sophia is completed, at staggering expense, in only five years.
The cathedral’s gigantic central dome, described by the contemporary author Procopius as "not founded on solid masonry but suspended from heaven by a golden chain," is surrounded on all sides by an outer shell of aisles and galleries.
Pendentives in the four corners round out the walls to meet the shallow dome, one hundred and twelve feet (thirty-four meters) in diameter, whose weight is borne by four gigantic exterior piers concealed behind the pendentives.
The interior's richly colored marbles and gleaming golden mosaics enhance the sparkling play of light through the numerous windows and apertures piercing the base of the dome.