معاوية بن أبي سفيان
Ali was assassinated, and died on the 21st of Ramadan in the city of Kufa (Iraq) in 661 CE by the Kharijite Abd-al-Rahman ibn Muljam. Ali's son Hasan briefly succeeded as caliph before abdicating the caliphate in favour of Muawiyah I in order to end the civil war.