This is a repeat of questions 97 and 162. The tragedy of Karbala occurred in 61 AH (680 CE) on the 10th of Muharram (Day of Ashura). Imam Hussain (RA), grandson of the Prophet (PBUH), along with his family and companions, was martyred by Yazid's forces. This event profoundly impacted Islamic history and is commemorated annually, particularly by Shia Muslims through mourning rituals during the first ten days of Muharram.