The Orthodox Church is thus a family of self-governing Churches. It is held together, not by a centralized organization, not by a single prelate wielding absolute power over the whole body, but by the double bond of unity in the faith and communion in the sacraments. Each Church, while independent, is in full agreement with the rest on all matters of doctrine, and between them all there is full sacramental communion. (Certain divisions exist among the Russian Orthodox, but the situation here is altogether exceptional and, one hopes, temporary in character).
There is in Orthodoxy no one with an equivalent position to the Pope in the Roman Catholic Church. The Patriarch of Constantinople is known as the "Ecumenical" (or universal) Patriarch, and since the schism between east and west he has enjoyed a position of special honor among all the Orthodox communities; but he does not have the right to interfere in the internal affairs of other Churches. His place resembles that of the Archbishop of Canterbury in the worldwide Anglican communion.
This decentralized system of independent local Churches has the advantage of being highly flexible, and is easily adapted to changing conditions. Local Churches can be created, suppressed, and then restored again, with very little disturbance to the life of the Church as a whole. Many of these local Churches are also national Churches, for during the past in Orthodox countries Church and State have usually been closely linked. But while an independent State often possesses its own autocephalous Church, ecclesiastical divisions do not necessarily coincide with State boundaries. Georgia, for instance, lies within the U.S.S.R., but is not part of the Russian Church, while the territories of the four ancient Patriarchates fall politically in several different countries. The Orthodox Church is a federation of local, but not in every case national, Churches. It does not have as its basis the political principle of the State Church.
Among the various Churches there is, as can be seen, an enormous variation in size, with Russia at one extreme and Sinai at the other. The different Churches also vary in age, some dating back to Apostolic times, while others are less than a generation old. The Church of Czechoslovakia, for example, only became autocephalous in 1951.
Such are the Churches which make up the Orthodox communion as it is today. They are known collectively by various titles. Sometimes they are called the Greek or Greco-Russian Church; but this is incorrect, since there are many millions of Orthodox who are neither Greek nor Russian. Orthodox themselves often call their Church the Eastern Orthodox Church, the Orthodox Catholic Church, the Orthodox Catholic Church of the East, or the like. These titles must not be misunderstood, for while Orthodoxy considers itself to be the true Catholic Church, it is not part of the Roman Catholic Church; and although Orthodoxy calls itself eastern, it is not something limited to eastern people. Another name often employed is the Holy Orthodox Church. Perhaps it is least misleading and most convenient to use the shortest title: the Orthodox Church.
Orthodoxy claims to be universal — not something exotic and oriental, but simple Christianity. Because of human failings and the accidents of history, the Orthodox Church has been largely restricted in the past to certain geographical areas. Yet to the Orthodox themselves their Church is something more than a group of local bodies. The word "Orthodoxy" has the double meaning of "right belief" and "right glory" (or "right worship"). The Orthodox, therefore, make what may seem at first a surprising claim: they regard their Church as the Church which guards and teaches the true belief about God and which glorifies Him with right worship, that is, as nothing less than the Church of Christ on earth. How this claim is understood, and what the Orthodox think of other Christians who do not belong to their Church, it is part of the aim of this book to explain.
From "The Orthodox Church" by Timothy Ware.