Eastern Christianity comprises church families that developed outside the Occident, with major bodies including the Eastern Orthodox Church, the Oriental Orthodox churches, the Eastern Catholic Churches, and the denominations descended from the Church of the East. The Ukrainian Lutheran Church is also an Eastern Christian church that uses the Byzantine Rite. The term is used in contrast with Western Christianity, although its scope has been one of continual discussion. Eastern Christianity consists of the Christian traditions and churches that developed distinctively over several centuries in the Middle East, Africa, Eastern Europe, Asia Minor, the Malabar coast of South India, and parts of the Far East. The term does not describe a single communion or religious denomination. Some Eastern churches have more in common historically and theologically with Western Christianity than with one another. The various Eastern churches do not normally refer to themselves as "Eastern", with the exception of the Assyrian Church of the East and the Ancient Church of the East.
Monophysitism is the Christological position that, after the union of the divine and the human in the historical incarnation, Jesus Christ, as the incarnation of the eternal Son or Word (Logos) of God, had only a single "nature" which was either divine or a synthesis of divine and human. Monophysitism is contrasted to dyophysitism which maintains that Christ maintained two natures, one divine and one human, after the incarnation.
Chalcedonian Christianity refers to the Christian denominations adhering to the christological definitions and ecclesiological resolutions of the Council of Chalcedon, the Fourth Ecumenical Council held in 451. Chalcedonian Christians follow the Definition of Chalcedon, a religious doctrine concerning the divine and human natures of Jesus Christ. The great majority of Christian communions and confessions in the 21st century are Chalcedonian, but from the 5th to the 8th centuries the ascendancy of Chalcedonian Christology was not always certain.
Nestorius was Archbishop of Constantinople from 10 April 428 to August 431, when Emperor Theodosius II confirmed his condemnation by the Council of Ephesus on 22 June.
The Henotikon was a christological document issued by Byzantine emperor Zeno in 482, in an unsuccessful attempt to reconcile the differences between the supporters of the Council of Chalcedon and the council's opponents. It was followed by the Acacian schism.
A Christian denomination is a distinct religious body within Christianity, identified by traits such as a name, organization, leadership and doctrine. Individual bodies, however, may use alternative terms to describe themselves, such as church or sometimes fellowship. Divisions between one group and another are defined by authority and doctrine; issues such as the nature of Jesus, the authority of apostolic succession, eschatology, and papal primacy may separate one denomination from another. Groups of denominations—often sharing broadly similar beliefs, practices, and historical ties—are sometimes known as "branches of Christianity". These branches differ in many ways, especially through differences in practices and belief.
The School of Nisibis, for a time absorbed into the School of Edessa, was an educational establishment in Nisibis. It was an important spiritual centre of the early Church of the East, and like the Academy of Gondishapur, it is sometimes referred to as the world's first university. The school had three primary departments teaching: theology, philosophy and medicine. Its most famous teacher was Narsai, formerly head of the School of Edessa.
The School of Edessa, often confused with the School of Nisibis, was a theological school of great importance to the Syriac-speaking world. It had been founded as long ago as the 2nd century by the kings of the Abgar dynasty. In 363, Nisibis fell to the Persians, causing St. Ephrem the Syrian, accompanied by a number of teachers, to leave the School of Nisibis. They went to Edessa, where Ephrem took over the directorship of its school. Then, its importance grew still further. There were innumerable monasteries at Edessa housing many monks and offering many cells for their abode. Ephrem occupied a cell there, practicing the ascetic life, interpreting Holy Scripture, composing poetry and hymns and teaching in the school, as well as instructing young girls in church music.
Catholicos, plural Catholicoi, is a title used for the head of certain churches in some Eastern Christian traditions. The title implies autocephaly and in some cases it is the title of the head of an autonomous church. The word comes from ancient Greek καθολικός, pl. καθολικοί, derived from καθ' ὅλου from κατά and ὅλος, meaning "concerning the whole, universal, general"; it originally designated a financial or civil office in the Roman Empire. The name of the Catholic Church comes from the same word.
Syriac Christianity is the form of Eastern Christianity whose formative theological writings and traditional liturgy are expressed in the Syriac language.
Miaphysitism is Cyril of Alexandria's Christological formula holding that in the person of Jesus Christ, divine nature and human nature are united in a compound nature ("physis"), the two being united without separation, without mixture, without confusion and without alteration.
Non-Chalcedonianism is a religious doctrine of those Christian churches that do not accept the Confession of Chalcedon as defined at the ecumenical Council of Chalcedon in 451. The doctrine contrasts with Chalcedonian Christianity, which accepts the doctrines of the first seven Ecumenical Councils. Some Christian denominations do not accept the Confession of Chalcedon, for varying reasons, but accept the doctrines of the previous council at the Council of Ephesus in 431.
Eutychianism refers to a set of Christian theological doctrines derived from the ideas of Eutyches of Constantinople. Eutychianism is a specific understanding of how the human and divine relate within the person of Jesus Christ.
Syriac Christians are an ethnoreligious grouping of various ethnic communities of indigenous pre-Arab Semitic and often Neo-Aramaic-speaking Christian people of Iraq, Syria, Iran, Turkey, Lebanon, Jordan, Palestine, and Israel. Syriac Christians advocate different terms for ethnic self-designation. Syriac Christians from the Middle East are theologically and culturally closely related to, but should not be confused with the Saint Thomas Christians from India, whose ties to Syriac Christians were a result of trade links and migration by Assyrian Christians from Mesopotamia and the Middle East mostly around the 9th century.
Oriental Orthodoxy is the communion of Eastern Christian Churches that recognize only three ecumenical councils — the First Council of Nicaea, the First Council of Constantinople and the Council of Ephesus. They reject the dogmatic definitions of the Council of Chalcedon. Hence, these Churches are also called Old Oriental Churches or Non-Chalcedonian Churches.
Oriental Orthodoxy is the fourth largest communion of Christian churches, with about 76 million members worldwide. As one of the oldest religious institutions in the world, it has played a prominent role in the history and culture of Armenia, Egypt, Eritrea, Ethiopia, Sudan and parts of the Middle East and India. An Eastern Christian communion of autocephalous churches, its bishops are equal by virtue of episcopal ordination, and its doctrines can be summarised in that the communion recognizes the validity of only the first three ecumenical councils.
