Russia says it cannot participate in the Holy and Great Council as not all churches will be present at the meeting.
The meeting of Orthodox leaders is due to begin in Crete, Greece, on Sunday, to discuss the role of the church in the modern world.
There are about 100 million members of the Russian Orthodox Church.
The Orthodox Church:
- Independent and have their own leadership, unlike the Roman Catholics
- Clergy are distinguished by headgear and facial hair
- 300 million Orthodox Christians around the world
- 14 national churches
Earlier in the week the Russian Orthodox Patriarch Kirill, whose Church is boycotting the Holy and Great Council of the Eastern Orthodox, sent a message of encouragement to the Orthodox prelates in Greece.
The gesture came as leaders gathered in Crete for the Pan-Orthodox Council.
The 14 separate branches of the Orthodox church met last in 787, before they split with the Roman Catholic church.
The denomination split from western Christianity, what is now seen as Roman Catholicism, in 1054 amid disputes about how powerful Rome was.
This new meeting has been in the planning since 1961 and leaders represent around 300 million Orthodox Christians all around the world.
What will be discussed:
- The mission of the Orthodox church in the modern world
- The Orthodox Diaspora and which patriarchates can claim jurisdiction over the various members
- Autonomy and how it is proclaimed
- The sacrament of marriage and its impediments
- The importance of fasting and its observance in today's society
- Relations of the Orthodox church with the rest of the world
Many dynamics have been at play in the build up towards this historic meeting and there is also battle for power between Russia and the Istanbul-based Ecumenical Patriarch of Constantinople, Bartholomew I.
He is considered the spiritual head and "first among equals" and planned the meeting.
Problems arranging the meeting vary from who sits where to how the church can restore relations with the Vatican.
Around the world there are 300 million Orthodox Christians, who fall into 14 national Churches.
