The Siege of Jerusalem was part of a military conflict which took place in the year 637 between the Byzantine Empire and the Rashidun Caliphate. It began when the Rashidun army, under the command of Abu Ubaidah, besieged Jerusalem in November 636. After six months, the Patriarch Sophronius agreed to surrender, on condition that he submit only to the Rashidun caliph. In April 637, Caliph Umar traveled to Jerusalem in person to receive the submission of the city.