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.
Ecumenical Patriarch of Constantinople
The see of Byzantium, whose foundation was later ascribed to Andrew the Apostle, was originally a common bishopric. It gained importance when Emperor Constantine elevated Byzantium to a second capital alongside Rome and named it Constantinople. The see's ecclesiastical status as the second of five Patriarchates were developed by the Ecumenical Councils of Constantinople in 381 and Chalcedon in 451.