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.
Greek refugees
After the founding of Constantinople by the first Christian Roman Emperor Constantine the Great in 330, Asia Minor, the major part of the Greek East, became the most important region of the Eastern Roman (Byzantine) Empire. For the centuries to follow, the area was the main manpower and wheat source of the state. Numerous invasions and epidemics (especially the Plague of Justinian) devastated the area in various times. However, Asia Minor remained densely populated, compared to the rest of the Medieval world and held the bulk of the empire's Greek speaking orthodox Christian population. Thus, many renowned Greek-speaking figures who lived during this time were Asia Minor Greeks, including Saint Nicholas (270-343), John Chrysostomos (349-407), Isidore of Miletus (6th century), and Basilios Bessarion (1403-1472). The Greek speaking Christian population began to decline with the invasions of the Muslim Seljuq Turks in the 11th century. The establishment of the Seljuk Empire deprived the Byzantines of a large part of Asia Minor. The Fall of Constantinople on May 29, 1453, and the subsequent fall in 1461 of the Greek Empire of Trebizond, located along the eastern Black Sea coast, marked the end of Greek sovereignty in Asia Minor.