Patriarch of Moscow and all Rus' in the context of "Eastern orthodoxy"

Eastern Orthodoxy, otherwise known as Eastern Orthodox Christianity or Byzantine Christianity, is one of the three main branches of Chalcedonian Christianity, alongside Catholicism and Protestantism. Like the Pentarchy of the first millennium, the mainstream (or "canonical") Eastern Orthodox Church is organised into autocephalous churches independent from each other. In the 21st century, the number of mainstream autocephalous churches is seventeen; there also exist autocephalous churches unrecognized by those mainstream ones. Autocephalous churches choose their own primate. Autocephalous churches can have jurisdiction (authority) over other churches, some of which have the status of "autonomous" which means they have more autonomy than simple eparchies.

Many of these jurisdictions correspond to the territories of one or more modern states; the Patriarchate of Moscow, for example, corresponds to Russia and some of the other post-Soviet states. They can also include metropolises, bishoprics, parishes, monasteries, or outlying metochia corresponding to diasporas that can also be located outside the country where the primate resides (e.g., the case of the Ecumenical Patriarchate of Constantinople whose canonical territory is located partly in northern Greece and the east); sometimes they overlap (the case of Moldova where the jurisdictions of the patriarchs of Bucharest and of Moscow overlap).

The Russian Orthodox Church (ROC; Russian: Русская православная церковь, РПЦ, romanized: Russkaya pravoslavnaya tserkov, RPTs;), also officially known as the Moscow Patriarchate (Russian: Московский патриархат, romanized: Moskovskiy patriarkhat), is an autocephalous Eastern Orthodox Christian church. It has 194 dioceses inside Russia. The primate of the ROC is the patriarch of Moscow and all Rus'.

The history of the ROC begins with the Christianization of Kievan Rus', which commenced in 988 with the baptism of Vladimir the Great and his subjects by the clergy of the ecumenical patriarch of Constantinople. Starting in the 14th century, Moscow served as the primary residence of the Russian metropolitan. The ROC declared autocephaly in 1448 when it elected its own metropolitan. In 1589, the metropolitan was elevated to the position of patriarch with the consent of Constantinople. In the mid-17th century, a series of reforms led to a schism in the Russian Church, as the Old Believers opposed the changes.

Nikon (Russian: Ни́кон, Old spelling: Нїконъ), born Nikita Minin (Никита Минин; 7 May [O.S. 27 April] 1605 – 17 August [O.S. 7 August] 1681) was the seventh Patriarch of Moscow and all Rus' of the Russian Orthodox Church, serving officially from 1652 to 1666. He was renowned for his eloquence, energy, piety and close ties to Tsar Alexis of Russia. Nikon introduced many reforms, including liturgical reforms that were unpopular among conservatives. These divisions eventually led to a lasting schism known as Raskol (schism) in the Russian Orthodox Church. For many years, he was a dominant political figure, often equaling or even overshadowing the Tsar. In December 1667, Nikon was tried by a synod of church officials, deprived of all his sacerdotal functions, and reduced to the status of a simple monk.

The Russian Orthodox Church Outside of Russia (Russian: Ру́сская Правосла́вная Це́рковь Заграни́цей, romanized: Rússkaya Pravoslávnaya Tsérkov Zagranítsey, lit. 'Russian Orthodox Church Abroad'), also called Russian Orthodox Church Outside Russia or ROCOR, or Russian Orthodox Church Abroad (ROCA), is a semi-autonomous part of the Russian Orthodox Church (Moscow Patriarchate). Currently, the position of First-Hierarch of the ROCOR is occupied by Metropolitan Nicholas (Olhovsky).

The ROCOR was established in the early 1920s as a de facto independent ecclesiastical jurisdiction of Eastern Orthodoxy, initially due to lack of regular liaison between the central church authority in Moscow and some bishops due to their voluntary exile after the Russian Civil War. These bishops migrated with other Russians to Western European cities and nations, including Paris and other parts of France, and to the United States and other western countries. Later these bishops rejected the Moscow Patriarchate's unconditional political loyalty to the Bolshevik regime in the USSR. This loyalty was formally promulgated by the Declaration of 20 July 1927 of Metropolitan Sergius (Stragorodsky), deputy Patriarchal locum tenens. Metropolitan Anthony (Khrapovitsky), of Kiev and Galicia, was the founding First-Hierarch of the ROCOR.