List of Orthodox Churches

Orthodox Churches (those that use the word "Orthodox" in the name) belong mainly to two groups, Eastern Orthodoxy and Oriental Orthodoxy. Apart from these two groups, there are also other Churches of different traditions that call themselves Orthodox, such as the Communion of the Western Orthodox Churches.

The various autocephalous and autonomous synods of the Orthodox Church are distinct in terms of administration and local culture, but for the most part exist in full communion with one another. Presently, there are two communions that reject each other and in addition - some schismatic churches not in any communion, all three groups identifying as Eastern Orthodox. The main traditional historical communion are referred to as New Calendarists, who use a Revised Julian Calendar for calculating the feasts of the ecclesiastical year, another group are referred to as True Orthodoxy(also Old Calendarists), they are those who separated from the mainstream, have continued to use the old Julian Calendar claiming that the Calendar reform in 1920s is in contravention of the Ecumenical Councils. Similarly, another group called Old Believers, separated in 1666 from the official Russian Orthodox Church as a protest against church rite reforms introduced by Patriarch Nikon of Moscow. As Eastern Orthodox Christianity is both collegial and local in structure, there is no single organization called the "True Orthodox Church" nor is there official recognition among the "True Orthodox" as to who is properly included among them. While some unions have taken place even up to the present, the majority of True Orthodox are only secondarily concerned with reunion as opposed to preservation of Eastern Orthodox teaching.. The calendar question reflects the dispute between those who wish to synchronize with the modern Gregorian calendar, which its opponents consider unnecessary and damaging to continuity, and those who wish to maintain the traditional ecclesiastical calendar (which happens to be based on the Julian calendar), arguing that such a modern change goes against 1900 years of Church tradition and was in fact perpetrated without an ecumenical council, which would surely have rejected the idea.

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