The percentage of Christians in Turkey fell from 19 percent in 1914 or 3 million ( thought to be an undercount by one-third omitting 600,000 Armenians , 500,000 Greeks and 400,000 Assyrians ) to 2.5 percent in 1927 in a population of 14 million , due to events which had a significant impact on the country 's demographic structure , such as the Armenian Genocide , the population exchange between Greece and Turkey , and the emigration of Christians ( such as Levantines , Greeks , Armenians etc. ) to foreign countries ( mostly in Europe and the Americas ) that actually began in the late 19th century and gained pace in the first quarter of the 20th century , especially during World War I and after the Turkish War of Independence . Today there are more than 160,000 people of different Christian denominations , representing less than 0.2 percent of Turkey 's population , including an estimated 80,000 Oriental Orthodox , 35,000 Roman Catholics , 18,000 Antiochian Greeks , 5,000 Greek Orthodox and smaller numbers of Protestants ( Mostly ethnic Turkish ) . Currently there are 236 churches open for worship in Turkey . The Eastern Orthodox Church has been headquartered in Istanbul since the 4th century
Armenian Genocide
Armenian Genocide
Christianity in the Middle East