Orthodox Christian church leaders from around the world met for the first such gathering in a millennium, but the landmark event was overshadowed by the decision by Russia's patriarch to stay away.
Clerics celebrated the event known as the Pentecost on the Greek island of Crete on June 19, where a "divine liturgy" was performed as part of the assembly that will last until June 27.
Ecumenical Patriarch Bartholomew called the "Holy and Great Council" for leaders to discuss wedlock, fasting, and other social issues.
But Russian Patriarch Kirill did not attend, mainly in solidarity with church leaders from Bulgaria, Serbia, and Syria, who are staying away over organizational differences.
The Russian Orthodox Church represents about 130 million faithful, or half the world's Orthodox population.
The boycott has undermined the image of unity that the gathered leaders had sought to project.
With reporting by AP and Reuters