Second Syria campaign of Ali

The Second Syria campaign of Ali refers to the abortive efforts of Ali ibn Abi Talib, the Muslim caliph (r. 656–661) and the first Shia Imam, to organize a renewed military campaign against Mu'awiya, the governor of Syria. Following the indecisive Battle of Siffin against Mu'awiya in 657 CE, Ali subdued the Kharijites revolt in the Battle of Nahrawan in 658, but his military coalition in Iraq collapsed afterward when the tribal chiefs withdrew their support, as they hoped for peace with Mu'awiya on beneficial terms.

Source: Wikipedia — Second Syria campaign of Ali (CC BY-SA 4.0)