Christianity is a minority religion in Turkey today, though it was once the majority faith of the Ottoman Empire. The Christian population shrank immensely with the forfeiture of large territories leading up to and during WWI, and with the population transfer between Turkey and Greece that saw the loss of most of Turkey’s Greek Orthodox community. Christians currently make up less than 0.3% of the population, including (from largest to smallest) Armenian Orthodox Christians, Roman Catholics, Syrian Orthodox Christians, Russian Orthodox Christians, Jehovah’s Witnesses, other Protestants, and small communities of Iraqi Chaldean Christians, Greek Orthodox Christians, and other Christian denominations.
Sources:
Bureau of Democracy, Human Rights and Labor, “International Religious Freedom Report for 2012: Turkey,” HumanRights.gov (2012), accessed November 4, 2013.