Christianity was introduced to the coastal plain of Lebanon from neighboring Galilee, already in the 1st century. The region, as with the rest of Syria and much of Anatolia, became a major center of Christianity. In the 4th century it was incorporated into the Christian Byzantine Empire. Mount Lebanon and its coastal plain became part of the Diocese of the East, divided to provinces of Phoenice Paralia and Phoenice Libanensis (which also extended over large parts of modern Syria).