Khalid ibn Walid was from the Meccan tribe of Quraysh, who opposed Muhammad, and he played a vital role in their victory at the Battle of Uhud. He converted, however, and joined Muhammad after the Treaty of Hudaybiyyah and commanded various expeditions for him. After Muhammad's death, he played a key role in commanding Medinan forces for Abu Bakr in the Ridda wars, the capture of the Sassanid Arab client Kingdom of Al-Hirah, and the defeat of the Sassanid Persian forces during his conquest of the Persian Empire.