Abu Ubaidah ibn al-Jarrah
Khalid set off with his army towards Sham and opened Bosra and then defeated the Byzantines at the Battle of Ajnadayn. After Umar ibn Al-Khattab became caliph in 13 AH (634 AD), Khalid was replaced by Abu Ubaidah ibn al-Jarrah. Abu Ubaidah was ordered to complete the conquest. He took Damascus, Baalbek, Homs, Hama and Latakia.