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.
Roman emperor
The line of Roman emperors in the Eastern Roman Empire continued unbroken at Constantinople until the capture of Constantinople in 1204 by the Fourth Crusade. In the wake of this action, four lines of Emperors emerged, each claiming to be the legal successor: the Empire of Thessalonica, evolving from the Despotate of Epirus, which was reduced to impotence when its founder Theodore Komnenos Doukas was defeated, captured and blinded by the Bulgarian Emperor Ivan Asen III; the Latin Empire, which came to an end when the Empire of Nicaea recovered Constantinople in 1261; the Empire of Trebizond, whose importance declined over the 13th century, and whose claims were simply ignored; and the Empire of Nicaea, whose claims based on kinship with the previous emperors, control of the Patriarch of Constantinople, and possession of Constantinople through military prowess, prevailed. The successors of the emperors of Nicaea continued until the fall of Constantinople in 1453 under Constantine XI Palaiologos.