John Allen provides a good "backgrounder" to Pope Benedict's upcoming trip to Turkey, which starts on November 28th. He notes that while Turkey is one of the few Islamic states where conversion is not illegal, significant restrictions on religious freedom remain and the Christian communities in the country face significant challenges:

Exact numbers are difficult to come by, but by any standard Turkey's Christians represent a tiny minority. The Patriarch of Constantinople presides over perhaps as few as 2,000 souls. The Greek Orthodox presence in Turkey was eviscerated by a "population exchange" between Greece and Turkey in 1922, when almost a million and half Turkish citizens who were Orthodox Christians were sent packing to Greece, while a million Muslims in Greece were thrust into Turkey. There are still some 100,000 Armenian Christians in Turkey, along with roughly 30,000 Catholics divided across a variety of rites.

Whatever their numbers, there's no doubt that Christians face serious challenges, some of which are a de jure matter of formal discrimination. Christians, for example, are barred from careers in the military, which is the ultimate source of power and prestige in Turkish society. Christian clergy usually are refused Turkish citizenship, no matter how long they've been in the country. Only recently have they been able to obtain residency permits valid for more than a few months, paying a tax of 0.50 Euro (about 64 U.S. cents) for every day in the country. Because Christian churches have no legal personality, parishes and schools have to be bought and sold in the name of private Turkish citizens, a requirement that generates all manner of property disputes and administrative headaches. Seminaries for both the Patriarch of Constantinople and the Armenian Orthodox Church have been closed by government order since 1971.