وقعة صفين
He refused Ali's demands for allegiance. He insisted on Levant autonomy under his rule and refused to pay homage to Ali on the pretext that his contingent had not participated in the election. Ali then moved his armies north and the two sides encamped at Siffin for more than one hundred days, most of the time being spent in negotiations. Although Ali exchanged several letters with Muawiyah, he was unable to dismiss the latter, nor persuade him to pledge allegiance. Skirmishes between the parties led to the Battle of Siffin in 657.