https://orthodoxwiki.org/List_of_autocephalous_and_autonomous_churches
It's complicated and goes back a long way, and there are multiple layers to it.
One
layer is that the Moscow patriarchate is loyal to the Russian state,
and has been since the Soviet Union, whereas the Greek patriarchate,
though it's located in Turkey, actually exercises most of its power in
the United States, and has a longstanding relationship with American
intelligence. So that rivalry has been in place since before the Cold
War.
It goes back older than that though. Moscow has, at times,
been considered the 3rd Rome, Rome being the greatest seat of power in
the Church. Constantinople, the home of the Greek patriarchate, is the
2nd Rome, and tends not to be a fan of this designation for obvious
reasons.
The autocephalous and autonomous Orthodox churches are those churches (i.e. jurisdictions)
which have self-government. These jurisdictions are united in doctrine
and worship, they recognize each other as canonical, they are in full communion, and together they constitute the Orthodox Church.
The use of the term "churches" to refer to the various jurisdictions is
informal; strictly speaking, they are just parts of the One Church, the
Orthodox Church.
Almost two thousand years ago, Jesus Christ, the Son of God, came to
earth and founded the Church, through His Apostles and disciples, for
the salvation of man. In the years which followed, the Apostles spread
the Church and its teachings and founded many churches, all united in
faith, worship, and the partaking of the Mysteries (or as they are
called in the West, the Sacraments) of the Holy Church. The churches
founded by the Apostles themselves include the Patriarchates of
Alexandria, Antioch, Jerusalem, and Rome and Constantinople. The Church of Alexandria was founded by St. Mark, the Church of Antioch by St Paul, the Church of Jerusalem by Ss. Peter and James, the Church of Rome by Ss. Peter and Paul, and Church of Constantinople by St Andrew. Those founded in later years through the missionary activity of the first churches were the Churches of Sinai, Russia, Greece, Serbia, Bulgaria, Romania, and many others.
Church of the Holy Sepulchre (Jerusalem)
The three, first appointed when Crusaders held Jerusalem, are the (Greeks) Orthodox, the Armenian Apostolic and Roman Catholic Churches. These remain the primary custodians of the church. In the 19th century, the Coptic Orthodox, the Ethiopian Orthodox and the Syrian Orthodox acquired lesser responsibilities,
Minimal list
This is a list of churches that are recognized as autocephalous or autonomous by all the others. They are shown here in the canonical order established by Church Tradition.
Autocephalous churches
Autonomous churches
Expanded list
This is a list of churches that are recognized as autocephalous or autonomous by at least some of the others. They are also shown here in canonical order.
Autocephalous churches
It should be noted that in the diptychs
of the Moscow Patriarchate and some of its daughter churches (e.g. the
OCA), the ranking of four of the patriarchal churches is different.
Following Moscow in rank is Georgia, then Serbia, Romania, and Bulgaria.
The remainder of the rankings beginning with Cyprus is the same.
Autonomous churches
Former self-governing churches
These churches were formerly autocephalous or autonomous, but they are no longer Orthodox, or in some cases no longer exist.
Churches in schism
The following churches are in schism
from the mainstream Orthodox Church. In other words, they are not in
communion and not considered part of the Orthodox Church, although in
most cases they maintain the same doctrine and the same practices.