Military confrontations with the Byzantine Empire began during the lifetime of Muhammad. The Battle of Mu'tah was fought in September 629 near the village of Mu'tah, east of the Jordan River and Karak in Karak Governorate, between the forces of the Islamic prophet Muhammad and of the Byzantine Empire and their Arab Christian Ghassanid vassals. In Islamic historical sources, the battle is usually described as the Muslims' attempt to take retribution against the Ghassanids after a Ghassanid official executed Muhammad's emissary who was en route to Bosra. During the battle the Muslim army was routed. After three Muslim leaders were killed, the command was given to Khalid ibn al-Walid and he succeeded in saving the rest of the forces. The surviving Muslim forces retreated to Medina.