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.
Bosporus
On 29 May 1453, the then-emergent Ottoman Empire conquered the city of Constantinople following a lengthy campaign wherein the Ottomans constructed fortifications on each side of the strait, the Anadoluhisarı (1393) and the Rumelihisarı (1451), in preparation for not only the primary battle but to assert long-term control over the Bosporus and surrounding waterways. The final 53-day campaign, which resulted in Ottoman victory, constituted an important turn in world history. Together with Christopher Columbus's first voyage to the Americas in 1492, the 1453 conquest of Constantinople is commonly noted as among the events that brought an end to the Middle Ages and marked the transition to the Renaissance and the Age of Discovery.