Muawiyah ibn Abi Sufyan RA

Mu'awiyah ibn Abi Sufyan RA, son of Abu Sufyan ibn Harb RA, accepted Islam after the Conquest of Makkah and became one of the Prophet ﷺ's scribes. After Uthman RA's murder he demanded vengeance and led Syria against Ali RA in the civil strife, including Siffin in 37 AH; Sunni scholars hold that Ali was closer to the truth while both sides acted sincerely. After al-Hasan ibn Ali RA stepped down in 41 AH to reconcile the Muslims, Mu'awiyah became caliph, the first king in Islam and founder of the Umayyad dynasty, and he built the first Muslim naval forces.