The Greek Orthodox Church is under the protection of the State, which pays the clergy's salaries and Orthodox Christianity is the "prevailing" religion of Greece according to the Constitution. The Greek Orthodox Church is self-governing but under the spiritual guidance of the Ecumenical Patriarch in Constantinople. 98% of Greek citizens consider themselves members of the Orthodox Church, however, within the Greek Orthodox Church there is also a minority of believers (around 700,000) who adhere to the Julian Calendar and call themselves "Old Calendarists" or "Genuine Orthodox Christians".
The Muslim minority, concentrated in Thrace, was given legal status by provisions of the Treaty of Lausanne in 1923 and is Greece's only officially recognized religious minority. There are roughly 110,000 Greek Muslims concentrated in Rhodope prefecture (60,000), Xanthi prefecture (40,000) and Evros (about 10,000).
Catholics in Greece number about 50,000. They are concentrated on some of the Cyclades, remnants of the long Venetian rule over the islands. The largest communities are Syros (8,000) and Tenos (3,000).
Protestants (evangelicals) are of various denominations (Greek Evangelical, Free Evangelical, Pentecostal). There are an estimated 20,000 to 25,000 Protestants in Greece. The largest and oldest denomination are the Greek Evangelicals numbering about 15,000 persons. Their largest community - about 1,500 souls - is in Katerini.
Jehovah's Witnesses are found in major cities.
The recent influx of (mostly illegal) immigrants from Eastern Europe and the Third World has an expectedly varied multi-religious profile (Catholic, Muslim, Hindu etc).
Under the 2000 constitutional amendment, complete separation of church and state is being attempted, which clashes with both the population and the clergy. For example, numerous protests have occurred for the removal of the Religious Denomination entry from the National ID card. However, outside the Orthodox majority, many believe that Greece had and still has a serious problem of religious freedom.
- http://www.greekhelsinki.gr/bhr/english/organizations/ghm_mrgg_religious_freedom_2002.rtf Religious Freedom in Greece (September 2002)