Constantinople
Constantinople (; ) was the capital city of the Roman/Byzantine Empire (330–1204 and 1261–1453), and also of the brief Crusader state known as the Latin Empire (1204–1261), until finally falling to the Ottoman Empire (1453–1923). It was reinaugurated in 324 from ancient Byzantium as the new capital of the Roman Empire by Emperor Constantine the Great, after whom it was named, and dedicated on 11 May 330. The city was located in what is now the European side and the core of modern Istanbul.
Christianity in the 4th century
Constantine erected a new capital at Byzantium, a strategically placed city on the Bosporus. He renamed his new capital "Nova Roma" ("New Rome"), but the city would become known as Constantinople. The Second Ecumenical Council, held at the new capital in 381, elevated the see of Constantinople to a position ahead of the other chief metropolitan sees, except that of Rome. Mentioning in particular the provinces of Asia, Pontus and Thrace, it decreed that the synod of each province should manage the ecclesiastical affairs of that province alone, except for the privileges already recognized for Alexandria and Antioch.