Battle of Yarmouk
Muawiyah I's family, including his progenitors, Abu Sufyan ibn Harb and his wife Hind bint Utbah, were originally opponents of Islam and particularly of Muhammad until the Conquest of Mecca, but they converted to the religion in 630. However, many early history books, e.g., "The Islamic Conquest of Syria Fatuhusham", by al-Imam al-Waqidi, state that, after their conversion to Islam, Muhammad appointed Muawiyah I's father Abu Sufyan ibn Harb and his brother Yazid ibn Abi Sufyan as army commanders. Muawiyah I, Abu Sufyan ibn Harb, Yazid ibn Abi Sufyan and Hind bint Utbah fought in the Battle of Yarmouk. The defeat of the Byzantine Emperor Heraclius at the Battle of Yarmouk opened the way for Muslim expansion into Jerusalem and Syria.