Istanbul, Capital of the Ottoman Empire
When Constantinople fall, the church was severely threatened: the Turks were Islamic. The current patriarch thought how to convince the Sultan to let the church live, and then, he reached the idea: change the Sultan religion. With it speaking habilities, the patriarchs were able to win an special district statute in the Old City, and the Sultan built an palace outside the city and the palace he created in the old Acropolis was given to the Orthodox church. By that the patriarchs were able to hold the Orthodox as the major religion of the new Ottoman Sultanate and made the Russian Orthodox to remain in Russia.
Close to the World War, the Ottoman Sultan was having an faith crisis, and by that he stated to finish most of church privilegies that gained during the time that was the official religion. He converted to the Islamic church, ruled by the Syrian Caliphate, inside the Sultanate. To maintain the church, the Patriarch Constantine XXII were forced to declare independence from the Ottoman Sultanate in 1910, a little before the World War.
World War "Help"
Other problem of the Patriach, besides the Sultan and the Russian Orthodox was the Romanian Orthodox, that grow in Eastern Europe. During the war, Russia conquer the Romania Patriarchy and forced the Romanian destrution, and besides, the sultanate troops that could threatned the church were sent to the Austrian Front. By that, little Orthodox died in the East Ottoman Sultanate, but in the Western, many died in the front. By the Italian help, the Church received the independence and were able to join the Italian League.