<P> In 634 , Abu Bakr died and was succeeded by Umar , who continued his own war of conquest . In May 636 , Emperor Heraclius launched a major expedition to regain the lost territory , but his army was defeated decisively at the Battle of Yarmouk in August 636 . Thereafter , Abu Ubaidah , the Muslim commander - in - chief of the Rashidun army in Syria , held a council of war in early October 636 to discuss future plans . Opinions of objectives varied between the coastal city of Caesarea and Jerusalem . Abu Ubaidah could see the importance of both these cities , which had resisted all Muslim attempts at capture . Unable to decide on the matter , he wrote to Caliph Umar for instructions . In his reply , the caliph ordered them to capture the latter . Accordingly , Abu Ubaidah marched towards Jerusalem from Jabiya , with Khalid ibn Walid and his mobile guard leading the advance . The Muslims arrived at Jerusalem around early November , and the Byzantine garrison withdrew into the fortified city . </P>
<P> In 634 , Abu Bakr died and was succeeded by Umar , who continued his own war of conquest . In May 636 , Emperor Heraclius launched a major expedition to regain the lost territory , but his army was defeated decisively at the Battle of Yarmouk in August 636 . Thereafter , Abu Ubaidah , the Muslim commander - in - chief of the Rashidun army in Syria , held a council of war in early October 636 to discuss future plans . Opinions of objectives varied between the coastal city of Caesarea and Jerusalem . Abu Ubaidah could see the importance of both these cities , which had resisted all Muslim attempts at capture . Unable to decide on the matter , he wrote to Caliph Umar for instructions . In his reply , the caliph ordered them to capture the latter . Accordingly , Abu Ubaidah marched towards Jerusalem from Jabiya , with Khalid ibn Walid and his mobile guard leading the advance . The Muslims arrived at Jerusalem around early November , and the Byzantine garrison withdrew into the fortified city . </P>
who led the muslim forces that retook jerusalem
who led the muslim forces that retook jerusalem
Abu Ubaidah
Abu Ubaidah