Mu'awiyah I (Arabic: معاوية بن أبي سفيان; Transliteration: Mu‘āwīyah ibn Abī Sufyān; 602-680) was a companion of the Islamic prophet Muhamma and later the Umayyad caliph in Damascus. He engaged in a civil war against the fourth and final Rightly Guided Caliph, Ali (Muhammad's son-in-law) and met with considerable military success, including the seizure of Egypt. He assumed the caliphate after Ali's assassination in 661 and reigned until 680.