The struggle to establish Christianity as the new official religion of Rome and the resulting controversies reflect the political and religious turmoil of the centuries immediately following the birth of Jesus..."Early Christian" is a historical more than a stylistic designation. It refers roughly to the first five centuries AD and to Christian works of art made during that period. The term
Byzantine, derived from the city of Byzantium, is used to describe a style that originated in the Eastern Roman Empire, including works made in Italy under Byzantine influence. At first the two terms ovelap. However, as Rome and the Western Empire were overrun by northern European tribes and the East rose to prominence under Justinian, the distinction between the Eastern and the Western empires became more pronounced, and Early Christian and Byzantine cultures grew apart.