Query: Who was the third caliph?
Context: This caliphate was centered on the Umayyad dynasty (Arabic: الأمويون‎, al-ʾUmawiyyūn, or بنو أمية, Banū ʾUmayya, "Sons of Umayya"), hailing from Mecca. The Umayyad family had first come to power under the third caliph, Uthman ibn Affan (r. 644–656), but the Umayyad regime was founded by Muawiya ibn Abi Sufyan, long-time governor of Syria, after the end of the First Muslim Civil War in 661 CE/41 AH. Syria remained the Umayyads' main power base thereafter, and Damascus was their capital.