527–565

The reign of Justinian and the reconquest of the West

The reign of Justinian I (527–565) is regarded as the high point of the Eastern Roman (Byzantine) empire. He carried out a sweeping reform of law, the army, administration, and finances. In 533 he conquered Vandal Africa in half a year. From 535 to 553 he waged a devastating eighteen-year war against the Ostrogoths, restoring Italy and part of Spain to the empire. Yet its former grandeur was never fully recovered.

Justinian combined politics and theology. He championed a neo-Chalcedonian Christology in the spirit of Cyril of Alexandria ("one of the Trinity was incarnate") against Severus of Antioch, and sought to reconcile the Monophysites. He issued edicts against the Origenists (543) and defenders of the "Three Chapters" (544), and convened the Fifth Ecumenical Council (553).

Under him the Hagia Sophia was built in Constantinople as the architectural embodiment of his theological program.