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.
Treaty of Constantinople (1800)
The negotiations and mutual rivalties between Russia, the Porte, and the Islanders, led to the signing of the Treaty of Constantinople on 21 March 1800, which created the first autonomous Greek state since the Fall of the Byzantine Empire.