The Night of Imam Ali's (a.s.) Slaughter refers to the night of the 19th of Ramadan, when Imam Ali (a.s.) was wounded with a sword blow at dawn in the year 40 AH. This incident occurred in the Kufa Mosque by Ibn Muljam Muradi and led to the martyrdom of Imam Ali (a.s.) on the 21st of Ramadan.