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.
Constantine XI Palaiologos
Previously serving as regent for his brother John VIII 1437–1439, Constantine succeeded his brother, who died in Constantinople of natural causes in 1448, as Emperor following a short dispute with his younger brother Demetrios. Despite the mounting difficulties of his reign, contemporary sources generally speak respectfully of Constantine. Constantine would rule for just over 4 years, his reign culminating in the Ottoman siege and conquest of Constantinople, the imperial capital, under Sultan Mehmed II. Constantine did what he could to organize the defenses of the city, stockpiling food and repairing the old Theodosian walls, but the reduced domain of the Empire and the poor economy meant that organizing a force large enough for the defense of the city was impossible. Constantine led the defending forces, numbering approximately 7,000, against an Ottoman army numbering around 10 times that and died in the ensuing fighting.