Christianity in Turkey
Constantinople became established in the ecclesiastical hierarchy at the Council of Constantinople in 381. Second only to Rome, the legendary origins of the Patriarchate of Constantinople go back to St. Andrew, Metrophanes and Alexander of Constantinople. Constantinople's primacy over the Patriarchates of Alexandria and Antioch was reaffirmed at the Council of Chalcedon in 481, after which the papacy in Rome supported Constantinople in its dispute with Alexandria over monophysitism. Later, when Rome sought to assert its primacy over Byzantium, the Eastern Orthodox church developed the doctrine of pentarchy as a response.
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.