The pontiff will travel to Ankara, Istanbul, Ephesus and Izmir during his first visit to a predominantly Muslim country, the Vatican said, outlining for the first time the itinerary of the Nov. 28-Dec. 1 visit.
Other details will be announced later, the Vatican said, but the pilgrimage will begin in Ankara, the Turkish capital, and then take the pontiff to Izmir, a port city near Ephesus, which is an ancient Christian community, and finally to Istanbul, seat of the headquarters of the spiritual leader of the world's 200 million Orthodox Christians, Ecumenical Patriarch Bartholomew I.
Benedict will spend an entire day, Nov. 30, in Istanbul. The date is special to Orthodox faithful because it is the feast day of St. Andrew, who traveled across Asia Minor and is considered the father of the patriarchate of Constantinople, the Byzantine name for present-day Istanbul.
Turkey had extended an official invitation to the 79-year-old pontiff, and Benedict's choice of the Turkish capital as the first stop reflects this. Turkey, while predominantly Muslim, is officially secular.
The pontiff has said his meeting with Bartholomew is a priority of the pilgrimage. The Vatican has been working to overcome tensions with the Orthodox, especially in Russia and Ukraine, with an eye on a possible papal visit to Moscow that eluded Benedict's predecessor, John Paul II.
The Turkish visit was confirmed four days ahead of the Vatican's scheduled presentation of its annual message to mark the end of Ramadan, the Islamic world's month of fasting.
Benedict sparked protests across the Muslim world when he quoted a 14th century Byzantine emperor's criticism of Islam during a Sept. 12 speech in Germany. He has since expressed regrets that offense was taken, and reiterated his esteem for Islam.
Benedict also met with ambassadors from predominantly Muslim countries in a bid to defuse the anger.
On Saturday, Benedict's top aide, Cardinal Tarcisio Bertone, described the speech as an appeal for Christian-Muslim collaboration on moral goals, and the pontiff's visit to Turkey as part of dialogue between both sides.
Catholics and Muslims must "share themes of common interest and which are essential for the fate and future of humanity," Bertone, who is the Vatican's secretary of state, said on Italian state TV.
The Vatican is particularly keen on working with Islamic leaders to promote traditional family values, a common area of interest.
Bartholomew, who has his headquarters in Istanbul, had hoped that the pontiff would celebrate the saint's feast day there with him on Nov. 30, 2005. But the Turkish government, instead of approving of a visit last year, issued its own invitation to Benedict for 2006.
Bartholomew said earlier this month that he is eager to meet with Benedict as part of efforts on both sides to heal the long-standing rift between the Roman Catholic and Orthodox churches.
Benedict has embraced John Paul II's determination to improve relations among Christians.