Eastern Christianity

Eastern Christianity comprises Christian traditions and church families that originally developed during classical and late antiquity in the Eastern Mediterranean region or locations further east, south or north. The term does not describe a single communion or religious denomination. Eastern Christianity is a category distinguished from Western Christianity, which is composed of those Christian traditions and churches that originally developed further west.
Major Eastern Christian bodies include the Eastern Orthodox Church and the Oriental Orthodox Churches, along with those groups descended from the historic Church of the East, as well as the Eastern Catholic Churches, and the Eastern Protestant churches. Most Eastern churches do not normally refer to themselves as "Eastern", with the exception of the Assyrian Church of the East and its offshoot, the Ancient Church of the East.
The Eastern Orthodox are the largest body within Eastern Christianity with a worldwide population of 220 million, followed by the Oriental Orthodox at 60 million. The Eastern Catholic Churches consist of about 16–18 million and are a small minority within the Catholic Church. Eastern Protestant Christian churches do not form a single communion; churches like the Ukrainian Lutheran Church and the Malankara Mar Thoma Syrian Church have under a million members. The Assyrian Church of the East and the Ancient Church of the East, descendant churches of the Assyria-based Church of the East, have a combined membership of approximately 400,000.
Historically, Eastern Christianity was centered in the Middle East and surrounding areas, where Christianity originated. However, after the Muslim conquest of the Levant in the 7th century, the term Eastern Church increasingly came to be used for the Greek Church centered in Constantinople, in contrast with the Latin Church, centered on Rome, which uses the Latin liturgical rites. The terms "Eastern" and "Western" in this regard originated with geographical divisions in Christianity mirroring the cultural divide between the Hellenistic East and the Latin West, and the political divide of 395 AD between the Western and Eastern Roman Empires. Since the Protestant Reformation of the 16th century, the term "Eastern Christianity" may be used in contrast with "Western Christianity", which contains not only the Latin Church but also forms of Protestantism and Independent Catholicism. Some Eastern churches have more in common historically and theologically with Western Christianity than with one another.
Because the largest church in the East is the body currently known as the Eastern Orthodox Church, the term "Orthodox" is often used in a similar fashion to "Eastern", to refer to specific historical Christian communions. However, strictly speaking, most Christian denominations, whether Eastern or Western, regard themselves as "orthodox" as well as "catholic", and as sharing in the Four Marks of the Church listed in the Nicene-Constantinopolitan Creed : "One, Holy, Catholic and Apostolic".
Eastern churches utilize several liturgical rites: the Alexandrian Rite, the Armenian Rite, the Byzantine Rite, the East Syriac Rite, and the West Syriac Rite.

Families of churches

Eastern Christians do not all share the same religious traditions, but many do share cultural traditions. Christianity divided itself in the East during its early centuries both within and outside of the Roman Empire in disputes about Christology and fundamental theology, as well as through national divisions. It would be many centuries later that Western Christianity fully split from these traditions as its own communion. Major branches or families of Eastern Christianity, each holding a distinct theology and dogma, include the Eastern Orthodox Church, the Oriental Orthodox communion, the Eastern Catholic Churches and the Assyrian Church of the East.
In most Eastern churches, parish priests administer the sacrament of chrismation to infants after baptism, and priests are allowed to marry before ordination. The Eastern Catholic Churches recognize the authority of the Pope of Rome, but some of them who have originally been part of the Orthodox Church or Oriental Orthodox churches closely follow the traditions of Orthodoxy or Oriental Orthodoxy, including the tradition of allowing married men to become priests.
The Eastern churches' differences from Western Christianity have to do with theology, as well as liturgy, culture, language, and politics. For the non-Catholic Eastern churches, a definitive date for the commencement of schism cannot usually be given. The Church of the East declared independence from the churches of the Roman Empire at its general council in 424, which was before the Council of Ephesus in 431, and so had nothing to do with the theology declared at that council. Oriental Orthodoxy separated after the Council of Chalcedon in 451 but did not immediately form separate patriarchates until 518 and 536.
Since the time of the historian Edward Gibbon, the split between the Church of Rome and the Orthodox Church has been conveniently dated to 1054, though the reality is more complex. This split is sometimes referred to as the Great Schism, but is now more usually called the East–West Schism. This final schism reflected a larger cultural and political division which had developed in Europe and Southwest Asia during the Middle Ages and coincided with Western Europe's re-emergence from the collapse of the Western Roman Empire.
The Ukrainian Lutheran Church developed within Galicia around 1926, with its rites being based on the Liturgy of Saint John Chrysostom, rather than on the Western Formula Missae.

Eastern Orthodox Church

The Eastern Orthodox Church is a Christian body whose adherents are largely based in Western Asia and Turkey, Eastern Europe, the Balkans and the Caucasus, with a growing presence in the Western world. Eastern Orthodox Christians accept the decisions of the first seven ecumenical councils.
Eastern Orthodox Christianity identifies itself as the original Christian church founded by Christ and the Apostles, and traces its lineage back to the early Church through the process of apostolic succession and unchanged theology and practice. Characteristics of the Eastern Orthodox Church include the Byzantine Rite and an emphasis on the continuation of Holy Tradition, which it holds to be apostolic in nature.
The Eastern Orthodox Church is organized into self-governing jurisdictions along geographical, national, ethnic or linguistic lines. Eastern Orthodoxy is thus made up of fourteen or sixteen autocephalous bodies. Smaller churches are autonomous and each have a mother church that is autocephalous.
All Eastern Orthodox are united in doctrinal agreement with each other, though a few are not in communion at present, for non-doctrinal reasons. This is in contrast to the Catholic Church and its various churches. Members of the latter are all in communion with each other, parts of a top-down hierarchy. The Eastern Orthodox reject the Filioque clause as contrast to Catholics. The Catholic Church was once in communion with the Eastern Orthodox Church, but the two split after the East–West Schism and are no longer in communion.
It is estimated that there are approximately 240 million Eastern Orthodox Christians in the world. Today, many adherents shun the term "Eastern" as denying the church's universal character. They refer to Eastern Orthodoxy simply as the Orthodox Church.

Oriental Orthodoxy

Oriental Orthodoxy refers to the churches of Eastern Christian tradition that keep the faith of the first three ecumenical councils of the undivided Christian Church: the First Council of Nicaea, the First Council of Constantinople and the Council of Ephesus, while rejecting the dogmatic definitions of the Council of Chalcedon. Hence, these churches are also called the Old Oriental churches. They comprise the Coptic Orthodox Church, the Malankara Orthodox Church, the Eritrean Orthodox Tewahedo Church, the Ethiopian Orthodox Tewahedo Church, the Syriac Orthodox Church and the Armenian Apostolic Church.
Oriental Orthodoxy developed in reaction to Chalcedon on the eastern limit of the Byzantine Empire and in Egypt, Syria and Mesopotamia. In those locations, there are also Eastern Orthodox patriarchs, but the rivalry between the two has largely vanished in the centuries since the schism.

Church of the East

Historically, the Church of the East was the widest reaching branch of Eastern Christianity, at its height spreading from its heartland in Persian-ruled Assyria to the Mediterranean, India, and China. Originally the only Christian church recognized by Zoroastrian-led Sassanid Persia, the Church of the East declared itself independent of other churches in 424 and over the next century became affiliated with Nestorianism, a Christological doctrine advanced by Nestorius, Patriarch of Constantinople from 428 to 431, which had been declared heretical in the Roman Empire. Thereafter it was often known in the West, possibly inaccurately, as the Nestorian Church. Surviving a period of persecution within Persia, the Church of the East flourished under the Abbasid Caliphate and branched out, establishing dioceses throughout Asia. After another period of expansion under the Mongol Empire, the church went into decline starting in the 14th century, and was eventually largely confined to its founding Assyrian adherent's heartland in the Assyrian homeland, although another remnant survived on the Malabar Coast of India.
In the 16th century, dynastic struggles sent the church into schism, resulting in the formation of two rival churches: The Chaldean Catholic Church, which entered into communion with Rome as an Eastern Catholic Church, and the Assyrian Church of the East. The followers of these two churches are almost exclusively ethnic Assyrians. In India, the local Church of the East community, known as the Saint Thomas Christians, experienced its own rifts as a result of Portuguese influence.