As a horseman of the Quraysh's aristocratic Banu Makhzum, which ardently opposed Muhammad, Khalid played an instrumental role in defeating Muhammad and his followers during the Battle of Uhud in 625. In 627 or 629, he converted to Islam in the presence of Muhammad, who inducted him as an official military commander among the Muslims and gave him the title of Sayf Allah (lit. 'Sword of God'). During the Battle of Mu'tah, Khalid coordinated the safe withdrawal of Muslim troops against the Ghassanids. He also led the Bedouins under the Muslim army during the Muslim conquest of Mecca in 629–630 and the Battle of Hunayn in 630. After Muhammad's death, Khalid was appointed to Najd and al-Yamama with the purpose of suppressing or subjugating Arab tribes who were opposed to the Rashidun Caliphate; this campaign culminated in Khalid's victory over Arab rebel leaders Tulayha and Musaylima at the Battle of Buzakha in 632 and the Battle of Yamama in 633, respectively.
Khalid was subsequently assigned to Sasanian Mesopotamia in order to lead Muslim efforts against the Sasanian Empire, targeting Iranian military garrisons and Arab Christians. He was then reassigned to the Byzantine Levant by Abu Bakr in order to command Muslim armies against the Byzantine Empire; he led his troops there on an unconventional march across a long and waterless stretch of the Syrian Desert, boosting his reputation as a military strategist. As a result of decisive victories led by Khalid against the Byzantines at Ajnadayn (634), Fahl (634 or 635), Damascus (634–635), and the Yarmouk (636), the Rashidun army conquered most of the Levant. Khalid was subsequently demoted and removed from the army's high command by Umar. However, he continued service as a key lieutenant of his military successor, Abu Ubayda ibn al-Jarrah. Under Abu Ubayda, Khalid participated in the first siege of Emesa in 635 and the second siege of Emesa in 638, as well as in the siege of Aleppo and the Battle of Hazir in 637; these successive engagements collectively precipitated the Levantine retreat of Byzantine troops under Heraclius. Umar then dismissed Khalid from his position of governorship over Jund Qinnasrin around 638. Khalid died in either Medina or present-day Homs in 642.
He is generally considered by historians to be one of the most seasoned and accomplished generals of the early Islamic era, and he is likewise commemorated throughout the Arab world. Islamic tradition credits Khalid for his battlefield tactics and effective leadership of the early Muslim conquests, but also accuses him of illicitly executing Arab tribesmen who had accepted Islam—namely members of the Banu Jadhimah during the lifetime of Muhammad, and Malik ibn Nuwayra during the Ridda Wars—and being responsible for moral and fiscal misconduct in the Levant. Khalid's military fame disturbed some of the pious early Muslims, most notably Umar, who feared it could develop into a personality cult.
Ancestry and early life