Mu'awiya I

Mu'awiya ibn Abi Sufyan (c. 597, 603 or 605 – April 680), commonly known as Mu'awiya I, was the founder of the Umayyad Caliphate, ruling as the first caliph of the Umayyad dynasty from 661 until his death in 680. He became caliph less than thirty years after the death of the Islamic prophet Muhammad and immediately after the four Rashidun ('rightly-guided') caliphs. Unlike his predecessors, who had been close, early companions of Muhammad, Mu'awiya was a relatively late follower of Muhammad.

Mu'awiya and his father Abu Sufyan had opposed Muhammad, their distant Qurayshite kinsman and later Mu'awiya's brother-in-law, until Muhammad captured Mecca in 630. Afterwards, Mu'awiya became one of Muhammad's scribes. He was appointed by Caliph Abu Bakr (r. 632–634) as a deputy commander in the conquest of Syria. He moved up the ranks through Umar's caliphate (r. 634–644) until becoming governor of Syria during the reign of his Umayyad kinsman, Caliph Uthman (r. 644–656). He allied with the province's powerful Banu Kalb tribe, developed the defenses of its coastal cities, and directed the war effort against the Byzantine Empire, including the first Muslim naval campaigns.

In response to Uthman's assassination in 656, Mu'awiya took up the cause of avenging the murdered caliph and opposed the election of Ali. During the First Fitna, the two led their armies to a stalemate at the Battle of Siffin in 657, prompting an abortive series of arbitration talks to settle the dispute. Afterward, Mu'awiya gained recognition as caliph by his Syrian supporters and his ally Amr ibn al-As, who conquered Egypt from Ali's governor in 658. Following the assassination of Ali in 661, Mu'awiya compelled Ali's son and successor Hasan to abdicate and Mu'awiya's suzerainty was acknowledged throughout the Caliphate.