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.
Apostolic see
This Council of Nicaea, being held in 325, of course made no mention of Constantinople, a city which was only officially founded five years later, at which point it became the capital of the Empire. But the First Council of Constantinople (381) decreed in a canon of disputed validity: "The Bishop of Constantinople, however, shall have the prerogative of honour after the Bishop of Rome; because Constantinople is New Rome." A century after the Council of Chalcedon (451) and the ensuing schism between those who accepted it and those who rejected it, Eastern Orthodox Christianity wove these two sources together to develop the theory of the Pentarchy: "[F]ormulated in the legislation of the emperor Justinian I (527–565), especially in his Novella 131, the theory received formal ecclesiastical sanction at the Council in Trullo (692), which ranked the five sees as Rome, Constantinople, Alexandria, Antioch, and Jerusalem." Earlier, the Council of Ephesus decreed in 431 that the Church of Cyprus should be autocephalous, against the claims of Antioch, the capital of the Roman diocese of the East, of which Cyprus was part.