Between 636 and 637/38, during the Muslim conquest of the Levant, the Rashidun Caliphate took Jerusalem from the Byzantine Empire. It began when the Rashidun army, under the command of Abu Ubayda, besieged Jerusalem in November 636. After six months, Patriarch Sophronius agreed to surrender, on condition that he submit only to the caliph. In 637 or 638, Caliph Umar traveled to Jerusalem in person to receive the submission of the city. The patriarch thus surrendered to him.