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.
Ancient history
The Roman Empire underwent considerable social, cultural and organizational change starting with reign of Diocletian, who began the custom of splitting the Empire into Eastern and Western halves ruled by multiple emperors. Beginning with Constantine the Great the Empire was Christianized, and a new capital founded at Constantinople. Migrations of Germanic tribes disrupted Roman rule from the late 4th century onwards, culminating in the eventual collapse of the Empire in the West in 476, replaced by the so-called barbarian kingdoms. The resultant cultural fusion of Greco-Roman, Germanic and Christian traditions formed the cultural foundations of Europe.