<P> At the end of the 4th century the Roman Empire had effectively split into two parts although their economies and the Church were still strongly tied . The two halves of the Empire had always had cultural differences, exemplified in particular by the widespread use of the Greek language in the Eastern Empire and its more limited use in the West (Greek, as well as Latin, was used in the West, but Latin was the spoken vernacular). </P> <P> By the time Christianity became the state religion of the Empire at the end of the 4th century, scholars in the West had largely abandoned Greek in favor of Latin . Even the Church in Rome, where Greek continued to be used in the liturgy longer than in the provinces, abandoned Greek . Jerome's Vulgate had begun to replace the older Latin translations of the Bible . </P> <P> The 5th century would see further fracturing of the Church . Emperor Theodosius II called two synods in Ephesus, one in 431 and one in 449, the first of which condemned the teachings of Patriarch Nestorius of Constantinople, while the second supported the teachings of Eutyches against Archbishop Flavian of Constantinople . </P> <P> Nestorius 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 . Eutyches taught on the contrary that there was in Christ only a single nature, different from that of human beings in general . The First Council of Ephesus rejected Nestorius' view, causing churches centered around the School of Edessa, a city at the edge of the empire, to break with the imperial church (see Nestorian schism). </P>

Christianity became a legal religion in the roman empire under