In late 620s Muhammad had already managed to conquer and unify much of Arabia under Muslim rule, and it was under his leadership that the first Muslim-Byzantine skirmishes took place in response to Byzantine incursions. Just a few months after Heraclius and the Persian general Shahrbaraz agreed on terms for the withdrawal of Persian troops from occupied Byzantine eastern provinces in 629, Arab and Byzantine troops confronted each other at the Battle of Mu'tah as a result of Byzantine vassals murdering a Muslim emissary. Muhammad died in 632 and was succeeded by Abu Bakr, the first Caliph with undisputed control of the entire Arab peninsula after the successful Ridda Wars, which resulted in the consolidation of a powerful Muslim state throughout the peninsula.