Episcopalian government is adopted by the majority of churches, and for most of the history of Christianity it has been the only form known to Christendom. There are subtle differences in governmental principles, among episcopalian churches at the present time. To some extent the separation of episcopal churches can be traced to these differences in episcopal theory. The Catholic churches of Rome and Byzantium (Roman Catholic and Eastern Orthodox in modern terms) are episcopalian. N.B., Rome and Byzantium were, speaking generally, a single episcopalian government, one Church, until the Great Schism in 1054. Also, the non-Chalcedonian churches of the Orient (Nestorian) and Egyptian Coptic Orthodox (Monophysite), are episcopalian; however, differences concerning the person of Christ have caused these not to be in full communion with the Orthodox and the Catholics, ever since the Council of Chalcedon in the fifth century. Likewise, the Coptic Orthodox believe they have true apostolic succession; both the Greek and Coptic Orthodox churches have a Pope in Alexandria, both of whom trace their apostolic succession back to the Apostle Mark. There are official ongoing efforts in recent times to heal this ancient breach. Already, the two recognize each other's baptisms, chrismations, and marriages, making intermarriage much easier.
Catholic episcopalian government
The Roman Catholic Church is episcopalian with a single hierarchy terminating at the top with the Bishop of Rome. The basis of the system is grounded in the assertion that jurisdictional oversight of the Church is not a power that derives from human ambition, but strictly from the authority of Christ which was given to his twelve apostles. From this one authority, all legitimate, governmental representation of the authority of Christ on the earth is committed, by the Holy Spirit, through the laying on of hands, from the Apostles to the bishops, and from bishops to priests, in historical succession. In addition to the New Testament, one of the earliest of the Church fathers to define the importance of episcopalian government is Ignatius of Antioch. The unbroken line of the representation of Christ survived up to a certain historical point in four seats of Apostolic authority: Jerusalem, Antioch, Alexandria, and Rome. The Roman Catholic church believes that this apostolic succession continues to this day in itself; the Eastern Orthodox Church makes the same claim about itself. Both agree that apostolic succession means not only historical continuity, but that the church today preserves the same doctrines and practices that were taught by the original twelve apostles, who received them from Jesus Christ.
Constantine moved the Roman Empire from Rome to Constantinople, following the conquest of Licinius in 324. The seat of the Roman civilized world shifted to Greece and New Rome (Byzantium). Along with this shift, the effective administration of the Church also shifted. It was this practical eminence in the East that was acknowledged, first by the Council of Constantinople 381, and then ecumenically by the Council of Chalcedon in 451, so that the Patriarch (pre-eminent father) of the church under New Rome's domain was for all practical purposes the Bishop of Constantinople. Beginning with John the Faster, the Bishop of Constantinople adopted the title Ecumenical patriarch (pre-eminent father for the whole civilized world), to which the other Patriarchates assented. However, the episcopacy of Rome by virtue of its succession from the Apostles Peter and Paul, although the city was ruined, distant from the seat of secular power, and constantly harassed by invaders, claimed primacy for itself, and the title of "Apostolic See" - the last court of episcopal appeal in very serious matters.
Thus, two ideas of episcopalian succession competed, between Rome and Byzantium. In the East, the Apostolic authority speaking unitedly in episcopal council is primary; and through such a council the Bishop of Byzantium was granted primacy on par with Rome (which placed entire emphasis on episcopal succession from the Apostles). The differences, although subtle, produced a rift between the Bishop of Rome and the rest of Christendom, which continued with some occasional relief throughout much of the history of the Church until it finally ruptured with semi-finality in the Great Schism (marked by two dates: 16 July, 1054, and the Council of Florence in 1439). The conciliar idea of episcopal government continues in the Eastern Orthodox Church.
Today, the Roman Catholic Church sees the Roman Pope as the vicar or sole representative of Christ on Earth. The rest of the hierarchy descends from the Pope on down in a fairly linear fashion. In the Eastern Orthodox Church, the sixteen or so autocephalous patriarchs are seen as collectively gathering around Christ, with other archbishops and bishops gathering around them, and so forth, in a model called "conciliar hierarchy". This is based in part on the vision in the book of Revelation of the 24 elders gathered around the throne of Christ, who are believed to represent the 12 patriarchs of Israel and the 12 apostles of Jesus Christ. There is no single patriarch with exclusive authority comparable to the Pope of Rome.
Other protestant churches have adopted the episcopal form of government for practical, rather than historical reasons. These include the Methodist church and some of its offshoots and the Episcopal Church of Scotland. The Reformed church of France, and the Reformed Church of Hungary, and the Lutheran churches in the Old World may sometimes be called "episcopalian", but the more proper term is Synodical. In these latter cases, the form of government is not radically different from the presbyterian form, except that their councils of bishops have hierarchical jurisdiction over the local ruling bodies to a greater extent than in most Presbyterian and other Reformed churches. Old World Lutheranism, for historical reasons, has tended to adopt Erastian theories of episcopal authority (by which church authority is to a limited extent sanctioned by secular government), but church government is a matter without doctrinal significance. In America, the Lutheran churches tend to adopt a form of government more comparable to congregationalism.
See also: Bishop, Episcopal, Presbyterian, Congregationalist Church, AutocephalyProtestant episcopalian government
Among protestant churches, only the Church of England lays claim to episcopal succession in the terms comparable to the Catholic system. However, it has operated for more than five hundred years outside of the pale of Orthodoxy, and since this church does not acknowledge the primacy of Rome, it is not episcopacy in either the Eastern or the Roman sense. These claims have received some sympathy from both, the Catholic and Orthodox sides, but not officially.