The Islamization of Syria occurred as a result of the Muslim conquest
of Syria in 637 CE/AD. Until then, Syria was the main center of Eastern Christianity. The resulting mass
conversions from Christianity to Islam gradually took place over the course of
several centuries, such that Syria had become predominantly Muslim by 1000.
Conversion
to Islam had scarcely begun, apart from Arab tribes already settled in Syria;
except for the tribe of Ghassan, these all became Muslim.
