Constantinople
Constantinople (; ) was the capital city of the Roman/Byzantine Empire (330–1204 and 1261–1453), and also of the brief Crusader state known as the Latin Empire (1204–1261), until finally falling to the Ottoman Empire (1453–1923). It was reinaugurated in 324 from ancient Byzantium as the new capital of the Roman Empire by Emperor Constantine the Great, after whom it was named, and dedicated on 11 May 330. The city was located in what is now the European side and the core of modern Istanbul.
Ecumenical Patriarch of Constantinople
The see of Byzantium, whose foundation was later ascribed to Andrew the Apostle, was originally a common bishopric. It gained importance when Emperor Constantine elevated Byzantium to a second capital alongside Rome and named it Constantinople. The see's ecclesiastical status as the second of five Patriarchates were developed by the Ecumenical Councils of Constantinople in 381 and Chalcedon in 451.