Leading the ceremony, Patriarch Bartolomew I is in the strange position of a shepherd without a flock. In the decades since Turkey's independence in 1923, his Greek Orthodox community has dwindled from around 150,000 to 1,500 people, most of them elderly. And his role as spiritual head to Orthodox Christians worldwide has been curtailed, critics say, by Turkish restrictions.
Yet, Istanbul is where Pope Benedict XVI chose to make his first visit to the head of a church. He was driven, observers say, by a desire to further the healing process begun in 1964 between the churches of East and West, and, more controversially, to highlight concerns over Christian minorities in the Muslim world.
Surrounded by sharpshooters perched in olive groves, the pontiff delivered mass at the Shrine of Mary in western Turkey Wednesday, and said: "I turn to ... the little flock of Christ living in [Turkey's] midst to offer a word of encouragement and to manifest the affection of the whole church."
The Pope will be in Istanbul as a guest of Bartholomew until Friday. High on their agenda will be the future of the city's once-thriving Greek Orthodox community, and the patriarchate itself.
"The Turkish government limits our role, and places serious constrictions on us," says Father Alexander Karioutsos, of the Greek Orthodox Archdiocese of America. "We have a church whose body is greater than its head, because its head cannot grow."
Chief among Greek Orthodox grievances is the closure of a seminary to train priests on Halki island, just off Istanbul. Turkey closed the school in 1971 in line with strict secular laws that prohibit private religious higher education. Priests are currently trained in the U.S. and Greece. "Sure we can train priests elsewhere," says Karioutsos, "You can train a Catholic priest anywhere in the world, but training at the Vatican is completely different. We have a strong spiritual and historic connection here."
The Orthodox patriarchate has been located in this city, formerly known as Constantinople, since the fourth century. Despite pressure from the European Union, the Turkish government argues that opening the Halki school would put it under pressure to allow similar Islamic colleges a prospect deemed nightmarish by the secularist authorities.
Another ongoing bone of contention between Turkey and the Orthodox community is Ankara's refusal to recognise the patriarch as ecumenical, meaning head of the Orthodox Christian community worldwide. Turkey believes acknowledging this would be one step towards the patriarchate eventually demanding some form of autonomy on its territory, much like the Vatican. "The title ecumenical has accompanied the Patriarch for 15 centuries, it's not a 20th century invention," says Archbishop Demetrios of America. "It refers to a spiritual function."
The Orthodox church is hoping that Turkey's possible entry into the European Union will help give minority religions some political leverage. But given the increasing tension in relations between the E.U. and Turkey, the pronouncements of Benedict and Bartholomew will face intense scrutiny.