Turkey has a small but growing Greek population, most of whom are Greek Orthodox Christians. Greek Orthodox Christianity was one of three main groups under the Ottoman millet system, which dissolved with the creation of the secular state, at which point the Greek patriarch was temporarily expelled from Istanbul and secular education was imposed in Greek schools. Like the Armenians, the Greeks suffered massacres and expulsions from Turkey leading up to and during WWI, and many more were removed to Greece during the 1923 population transfer of Greeks and Turks.
The Greek Orthodox community anticipated that the reopening of the Halki Seminary—closed in 1971 during conflicts with Greece over Cyprus—would be among the changes made by Erdoğan’s 2013 democratic reforms package, but was not. Erdoğan’s statements regarding the seminary suggest that he is using it as leverage to urge the Greek government to approve the construction of mosques in Athens and the appointment of muftis in Thrace.
Sources:
Pinar Tremblay, “Erdogan Uses Christian Seminary As Chip in Talks With Greece,” Al-Monitor, October 14, 2013, accessed November 7, 2013.