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 (1454)
The Treaty of Constantinople was signed on April 18, 1454 between the Ottoman Empire and the Republic of Venice. It was the first treaty signed by the Turkish Sultan following the capture of Constantinople in 1453. It effectively ended Venetian aspirations to eliminate the Ottoman Empire or to conquer Constantinople on behalf of Christendom. The treaty gave the Republic of Venice freedom to trade in the Eastern Mediterranean.