Nestorian schism in the context of "Historian of Christianity"

The history of Christianity begins with Jesus, an itinerant Jewish preacher and teacher, who was crucified in Jerusalem c. AD 30–33. His followers proclaimed that he was the incarnation of God and had risen from the dead. In the two millennia since, Christianity has spread across the world, becoming the world's largest religion with over two billion adherents worldwide.

Initially, Christianity was a mostly urban grassroots movement. Its religious text was written in the first century. A formal church government developed, and it grew to over a million adherents by the third century. Constantine the Great issued the Edict of Milan legalizing it in 315. Christian art, architecture, and literature blossomed during the fourth century, but competing theological doctrines led to divisions. The Nicene Creed of 325, the Nestorian schism, the Church of the East and Oriental Orthodoxy resulted. While the Western Roman Empire ended in 476, its successor states and its eastern compatriot—the Byzantine Empire—remained Christian.

In the 5th century in Christianity, there were many developments which led to further fracturing of the State church of the Roman Empire. Emperor Theodosius II called two synods in Ephesus, one in 431 and one in 449, that addressed the teachings of Patriarch of Constantinople Nestorius and similar teachings. Nestorius had taught that Christ's divine and human nature were distinct persons, and hence Mary was the mother of Christ but not the mother of God. The Council rejected Nestorius' view causing many churches, centered on the School of Edessa, to a Nestorian break with the imperial church. Persecuted within the Roman Empire, many Nestorians fled to Persia and joined the Sassanid Church (the future Church of the East) thereby making it a center of Nestorianism. By the end of the 5th century, the global Christian population was estimated at 10-11 million. In 451 the Council of Chalcedon was held to clarify the issue further. The council ultimately stated that Christ's divine and human nature were separate but both part of a single entity, a viewpoint rejected by many churches who called themselves miaphysites. The resulting schism created a communion of churches, including the Armenian, Syrian, and Egyptian churches, that is today known as Oriental Orthodoxy. In spite of these schisms, however, the imperial church still came to represent the majority of Christians within the Roman Empire.

At the end of the 4th century the Roman Empire had effectively split into two states although its economy and the Church were still strongly tied. The two halves of the empire had always had cultural differences, in particular exemplified by the widespread use of the Greek language in the Eastern Empire and the more limited use of Greek in the West (Greek was used in the West but Latin was displacing it as the spoken vernacular. By the 5th century scholars in the West had begun to abandon Greek in favor of the use of Latin. The Church in Rome, in particular, began to encourage the use of Latin in the western provinces and published Jerome's Vulgate, the first authorized translation of the Bible in Latin.