Church of the East in the context of "Virgin Mary"

In the history of Christianity, the first seven ecumenical councils are as follows: the First Council of Nicaea in 325, the First Council of Constantinople in 381, the Council of Ephesus in 431, the Council of Chalcedon in 451, the Second Council of Constantinople in 553, the Third Council of Constantinople from 680 to 681 and finally, the Second Council of Nicaea in 787.

These seven events represented an attempt by Church leaders to reach an orthodox consensus, restore peace and develop a unified Christendom. Among Eastern Christians the Eastern Orthodox, Oriental Orthodox, and Church of the East (Assyrian) churches and among Western Christians the Roman Catholic, Anglican, Utrecht and Polish National Old Catholic, and some Scandinavian Lutheran churches all trace the legitimacy of their clergy by apostolic succession back to this period and beyond, to the earlier period referred to as the Early Church.

Apostolic succession is the method whereby the ministry of the Christian Church is considered by some Christian denominations to be derived from the apostles by a continuous succession, which has usually been associated with a claim that the succession is through a series of bishops. Those of the Catholic, Eastern Orthodox, Oriental Orthodox, Church of the East traditions maintain that a bishop's orders are neither regular nor valid without consecration through apostolic succession. These traditions do not always consider the episcopal consecrations of all of the other traditions as valid.

This series was seen originally as that of the bishops of a particular see founded by one or more of the apostles. According to historian Justo L. González, apostolic succession is generally understood today as meaning a series of bishops, regardless of see, each consecrated by other bishops, themselves consecrated similarly in a succession going back to the apostles. According to the Joint International Commission for Theological Dialogue Between the Catholic Church and the Orthodox Church, "apostolic succession" means more than a mere transmission of powers. It is succession in a church which witnesses to the apostolic faith, in communion with the other churches, witnesses of the same apostolic faith. The "see (cathedra) plays an important role in inserting the bishop into the heart of ecclesial apostolicity", but once ordained, the bishop becomes in his church the guarantor of apostolicity and becomes a successor of the apostles.

A Christian (/ˈkrɪstʃən, -tiən/ ) is a person who follows or adheres to Christianity, a monotheistic Abrahamic religion based on the life and teachings of Jesus Christ. Christians form the largest religious community in the world. The words Christ and Christian derive from the Koine Greek title Christós (Χριστός), a translation of the Biblical Hebrew term mashiach (מָשִׁיחַ) (usually rendered as messiah in English). While there are diverse interpretations of Christianity which sometimes conflict, they are united in believing that Jesus has a unique significance. The term Christian used as an adjective is descriptive of anything associated with Christianity or Christian churches, or in a proverbial sense "all that is noble, and good, and Christ-like."

According to a 2011 Pew Research Center survey, there were 2.3 billion Christians around the world, up from about 600 million in 1910. Today, about 37% of all Christians live in the Americas, about 26% live in Europe, 24% live in sub-Saharan Africa, about 13% live in Asia and the Pacific, and 1% live in the Middle East and North Africa. Christians make up the majority of the population in 158 countries and territories. 280 million Christians live as a minority. About half of all Christians worldwide are Catholic, while more than a third are Protestant (37%). Eastern Christians, including the Eastern Orthodox, Oriental Orthodox, and Church of the East, comprise 12% of the world's Christians. Other Christian groups make up the remainder. By 2050, the Christian population is expected to exceed 3 billion due to overall total fertility rate according to Pew Research Center. According to a 2012 Pew Research Center survey, Christianity will remain the world's largest religion in 2050, if current trends continue. In recent history, Christians have experienced persecution of varying severity, especially in the Middle-East, North Africa, East Asia, and South Asia.

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 (also called the Assyrian Church), as well as the Eastern Catholic Churches (which are in communion with Rome while maintaining Eastern liturgies), 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 Catholic Churches or Oriental Catholic Churches, also known as the Eastern-Rite Catholic Churches, Eastern Rite Catholicism, or simply the Eastern Churches, are 23 Eastern Christian autonomous (sui iuris) particular churches of the Catholic Church in full communion with the pope in Rome. Although they are distinct theologically, liturgically, and historically from the Latin Church, they are all in full communion with it and with each other. Eastern Catholics are a minority within the Catholic Church; of the 1.3 billion Catholics in communion with the pope, approximately 18 million are members of the Eastern churches. The largest numbers of Eastern Catholics are found in Eastern Europe, Eastern Africa, the Middle East, and India. As of 2022, the Syro-Malabar Church is the largest Eastern Catholic Church, followed by the Ukrainian Greek Catholic Church.

With the exception of the Maronite Church, the Eastern Catholic Churches are groups that, at different points in the past, used to belong to the Eastern Orthodox Church, the Oriental Orthodox churches, or the Church of the East; these churches underwent various schisms through history. Eastern Catholic Churches that were formerly part of other communions have been points of controversy in ecumenical relations with the Eastern Orthodox and other non-Catholic churches. The five historic liturgical traditions of Eastern Christianity, namely the Alexandrian Rite, the Armenian Rite, the Byzantine Rite, the East Syriac Rite, and the West Syriac Rite, are all represented within Eastern Catholic liturgy. On occasion, this leads to a conflation of the liturgical word "rite" and the institutional word "church". Some Eastern Catholic jurisdictions admit members of churches not in communion with Rome to the Eucharist and the other sacraments.

A hagiography (/ˌhæɡiˈɒɡrəfi/; from Ancient Greek ἅγιος (hágios) 'holy' and -γραφία (-graphía) 'writing') is a biography of a saint or an ecclesiastical leader, as well as, by extension, an adulatory and idealized biography of a preacher, priest, founder, saint, monk, nun or icon in any of the world's religions. Early Christian hagiographies might consist of a biography or vita (Latin for 'life', which begins the title of most medieval biographies), a description of the saint's deeds or miracles, an account of the saint's martyrdom (called a passio), or be a combination of these.

Christian hagiographies focus on the lives, and notably the miracles, ascribed to men and women canonized by the Roman Catholic church, the Eastern Orthodox Church, the Oriental Orthodox churches, and the Church of the East. Other religious traditions such as Buddhism, Hinduism, Taoism, Islam, Sikhism and Jainism also create and maintain hagiographical texts (such as the Sikh Janamsakhis) concerning saints, gurus and other individuals believed to be imbued with sacred power.

Prester John (Latin: Presbyter Ioannes) was a mythical Christian patriarch, presbyter, and king. Stories popular in Europe in the 12th to the 17th centuries told of a Nestorian patriarch and king who was said to rule over a Christian nation lost amid the pagans and Muslims in the Orient. The accounts were often embellished with various tropes of medieval popular fantasy, depicting Prester John as a descendant of the Three Magi, ruling a kingdom full of riches, marvels, and strange creatures.

At first, Prester John was imagined to reside in India. Tales of the Nestorian Christians' evangelistic success there and of Thomas the Apostle's subcontinental travels as documented in works like the Acts of Thomas probably provided the first seeds of the legend. As Europeans became aware of the Mongols and their empire, accounts placed the king in Central Asia, and eventually Portuguese explorers came to believe that the term was a reference to Ethiopia, which at that time was an isolated Christian "exclave" distant from any other Christian-ruled territory.

The Maphrian (Syriac: ܡܦܪܝܢܐ, romanized: maphryānā or maphryono), is the second-highest rank in the ecclesiastical hierarchy of the Syriac Orthodox Church, right below that of patriarch. The office of a maphrian is a maphrianate. There have been three maphrianates in the history of the Syriac Orthodox Church and one, briefly, in the Syriac Catholic Church.

The first maphrianate, called the Maphrianate of the East or the Maphrianate of Tagrit, was established in 628 to give the Syriac Orthodox Church an ecclesiastical hierarchy in the Sasanian Empire and lands outside the control of the Roman Empire. The seat of the bishop was initially at Tagrit and he ranked second in the hierarchy after the Patriarch of Antioch. Initially he used the title catholicos in direct opposition to the rival Catholicos of Seleucia-Ctesiphon of the Church of the East. The title "maphrian" first came into use around 1100. In 1156 the seat of the maphrian was moved to Mosul. The Maphrianate of the East was abolished in 1860 as a result of a decreasing number of Syriac Orthodox outside of the region of Ṭur ʿAbdin. By then it had been a merely titular see for a long time.

In the year before the First Council of Constantinople in 381, Nicene Christianity became the official religion of the Roman Empire when Theodosius I, emperor of the East, Gratian, emperor of the West, and Gratian's junior co-ruler Valentinian II issued the Edict of Thessalonica in 380, which recognized the catholic orthodoxy, as defined by the Council of Nicea, as the Roman Empire's state religion. Historians refer to this state-sponsored church using a variety of terms: the catholic church, the orthodox church, the imperial church, the Roman church, or the Byzantine church, with some also used for wider communions extending beyond the Roman Empire. The Eastern Orthodox Church, Oriental Orthodoxy, and the Catholic Church all claim to stand in continuity from the Nicene Christian church to which Theodosius granted recognition. Political differences between the Eastern Roman Empire and the Persian Sassanid Empire led to the separation of the Church of the East in 424. A doctrinal split within the imperial church led to the independence of early Oriental Orthodoxy, while the fall of the Western Roman Empire initiated the gradual separation between Eastern and Western Christianity, culminating in the East-West schism of 1054. The Western Church evolved into the Latin Catholic Church while the Eastern Church that remained under the patronage of the Eastern empire and evolved into the Greek Orthodox Church.

Earlier in the 4th century, following the Diocletianic Persecution of 303–313 and the Donatist controversy that arose in consequence, Constantine the Great had convened councils of bishops to define the orthodoxy of the Christian faith and to expand on earlier Christian councils. A series of ecumenical councils convened by successive Roman emperors met during the 4th and the 5th centuries, but Christianity continued to suffer rifts and schisms surrounding the theological and christological doctrines of Arianism, Nestorianism, Miaphysitism, and Dyophysitism. In the 5th century, the Western Roman Empire decayed as a polity; invaders sacked Rome in 410 and in 455, and Odoacer, an Arian barbarian warlord, forced Romulus Augustus, the last nominal Western Emperor, to abdicate in 476. However, apart from the aforementioned schisms, the church as an institution persisted in communion, if not without tension, between the East and West. In the 6th century, the Byzantine armies of the Byzantine Emperor Justinian I recovered Italy and other regions of the Western Mediterranean shore. The Byzantine Empire soon lost most of these gains, but it held Rome, as part of the Exarchate of Ravenna, until 751, a period known in church history as the Byzantine Papacy. The early Muslim conquests of the 7th–9th centuries would begin a process of converting most of the then-Christian world in the Levant, Middle East, North Africa, regions of Southern Italy and the Iberian Peninsula to Islam, severely restricting the reach both of the Byzantine Empire and of its church. Christian missionary activity directed from the capital of Constantinople did not lead to a lasting expansion of the formal link between the church and the Byzantine emperor, since areas outside the Byzantine Empire's political and military control set up their own distinct churches, as in the case of Bulgaria in 919.