Turkey allowed Christians to hold a rare service at a politically sensitive monastery for the first time since the modern-day country's creation nearly nine decades ago.
Sunday's Mass at the ancient monastery of Sumela near the Black Sea was led by Patriarch Bartholomew I, the spiritual leader of the world's Orthodox Christians.
Over 1,500 pilgrims from Greece, Russia and other countries traveled to the Byzantine-era monastery for the emotional, three-hour service – the first of two that Turkey's government has permitted this summer.
According to reports, Turkey's Culture Ministry said the decision to open the two churches was a result of the ministry's "evaluation that visitor activity brought by belief tourism would contribute in solving economic, political and social problems in these regions and would have a positive impact on relations with neighboring countries."
Some observers, however, believe the move is part of the Turkish government's effort to improve its public relationship with ethnic and religious minorities amid its bid to join the European Union.
Despite the government's latest efforts, however, activists say the change is too slow.
A key Orthodox Christian demand is the reopening of the Halki Theological School near Istanbul, which was closed to new students in 1971 after a law put religious and military training under state control.
Within Turkey's predominantly-Muslim population of 72 million people, the Greek Orthodox community stands at about 2,000.