In 638 C.E. Christian Jerusalem fell to a minor Arab officer by the name of Khalid ibn Thabit from the clan of Fahm. The patriarch of Jerusalem, Sophronius, had by then lost all hope of relief from Constantinople, since all the major cities of Syria (including Damascus) had opened their gates to the invading Muslim armies.
Most of these armies had already moved north or south, subjugating whatever remained of the Syrian and African provinces of the Byzantine empire. Caesarea alone refused to capitulate and was brought under siege, which cut it off from the Palestinian hinterland but not from marine lines of communication with the center of the empire in Constantinople. Soon, however, Caesarea would succumb to Muslim armies headed by Mu‘awiyah—an Arab aristocrat who belonged to the Umayyah family in Mecca and who, 20 years later, would become the first member of the Umayyad dynasty to rule the new Islamic empire.