The last large garrison of the Byzantine army was at Fahl, which was joined by survivors of Ajnadayn. With this threat at their rear the Muslim armies could not move further north nor south, thus Abu Ubaidah decided to deal with the situation, and defeated and routed this garrison at the Battle of Fahl on 23 January 635, which proved to be the "Key to Palestine". After this battle Abu Ubaidah and Khalid marched north towards Emesa; Yazid was stationed in Damascus while Amr and Shurhabil marched south to capture Palestine.