: Constantine established a new capital at Constantinople (modern-day Istanbul), strategically located on the Bosphorus to control trade between Europe and Asia.
: Justinian commissioned the Hagia Sophia , a feat of engineering that remained the world’s largest cathedral for nearly a millennium. A History of Byzantium
: Emperor Justinian I (r. 527–565) sought to reclaim the lost Western provinces, briefly retaking Italy, North Africa, and parts of Spain. : Constantine established a new capital at Constantinople
: Facing a Crisis of the Third Century , Emperor Diocletian divided the Roman Empire into East and West to make it more governable. briefly retaking Italy
: Unlike the pagan Rome of old, Byzantium was defined by its integration of Roman law, Greek culture, and Christian theology.