Ammar ibn Yasir
(), was one of the Muhajirun in the history of Islam and, for his dedicated devotion to Islam's cause, is considered to be one of the most loyal and beloved companions of Muhammad and ‘Ali and to Muslims; thus, he occupies a position of the highest prominence in Islam. Historically, Ammar ibn Yasir is the first Muslim to build a mosque. He is also referred to by Shia Muslims as one of the Four Companions. Muslims consider Ammar's ultimate fate to be unique among the fates of Muhammad's companions, for they perceive his death at the battle of Siffin as the decisive distinguisher between the righteous group and the sinful one in the First Fitna.