Byzantine architecture had its roots in Constantinople (present-day Istanbul, Turkey) but spread throughout the Byzantine Empire in eastern Mediterranean and Near East area. The era started around 400 AD and lasted until 1453.
Constantinople was founded upon the premise that it would be a Christian capital. Because of that, churches were erected with Byzantine influence of domes, rounded arches and intricate interior mosaics. It also utilized the Greek cross, which each arm of the cross is equal. The Architecture: A Spotter’s Guide described Byzantine architecture in the following way:
Typically, the Byzantine structure appears squat and solid from the outside; within, though, the impression is of weightlessness and light. Another Roman technique – that of mosaic – was used to shimmering effect to give an extraordinary sense of spiritual transcendence.
One of the most famous Byzantine structure is the Hagia Sophia (“Holy Wisdom”). Procopius, a Byzantine historian, once stated that the Hagia Sophia “seems not to rest upon solid masonry, but to cover the space with its golden dome suspended from heaven.” The emperor Justinian enlisted architects, Anthemius of Tralles and Isidore of Miletus, to build a great Constantinople church. It took almost six years (from 531-532 to 537) to build the Hagia Sophia. The design proved to be so daring that the dome collapsed twice, once because of an earthquake. In 1346, construction on the dome was finally completed. The only change from 1346 to the present was the addition of four minarets, which are tall spires common to Islamic mosque architecture. The Hagia Sophia was built as a Greek Orthodox cathedral but during the Ottoman rule it was converted into a mosque.
Cunliffe, Sarah, Sara Hunt and Jean Loussier. Architecture: A Spotter’s Guide. New York: Metro Books, 2010, 30-31.
The Hagia Sophia website.