After Uthman was killed, he was elected the fourth caliph of the Muslims. His caliphate coincided with the first civil wars between Muslims. Ali faced two separate opposition forces: a group led by Aisha, Talhah, and Zubayr in Mecca, who wanted to convene a council to determine the caliphate. And another group led by Muawiyah in the Levant who demanded revenge for Uthman's blood. Four months after his caliphate, Ali defeated the first group in Battle of the Camel; But in the end, Battle of Siffin with Muawiyah was militarily ineffective, and led to an arbitration which ended politically against Ali. Then, in the year 38 AH, he fought with the Kharijites - who considered Ali's acceptance of arbitration as heresy, and revolted against him - in Nahrawan and defeated them. Ali was eventually killed in the mosque of Kufa by the sword of one of the Kharijites, Ibn Muljam Moradi, and was buried outside the city of Kufa. Later his shrine and the city of Najaf were built around his tomb.