Husayn ibn ‘Alī ibn Abī Tālib (Arabic: الحسين بن علي بن أبي طالب; 08 January 626 AD – 10 October 680 AD) (3rd / 4th Sha'aban 4 AH – 10th Muharram 61 AH), sometimes spelled Hussein, was the son of Ali ibn Abi Ṭalib (fourth Rashidun Caliph of Sunni Islam, and first Imam of Shia Islam) and Fatimah Zahra (daughter of Muhammad) and the younger brother of Hasan ibn Ali. Husayn is an important figure in Islam, as he is a member of the Ahl al-Bayt (the household of Muhammad) and Ahl al-Kisa, as well as being the third Shia Imam.Husayn is highly regarded by Shiite Muslims because he refused to pledge allegiance to Yazid I, the Umayyad caliph because he considered the rule of the Umayyads unjust. As a consequence, he left Medina, his home town, and traveled to Mecca. At Karbala his caravan was intercepted by Yazid I's army. He was killed and beheaded in the Battle of Karbala in 680 (61 AH) by Shimr Ibn Thil-Jawshan, along with most of his family and companions. The annual memorial for him, his family, his children and his companions is called Ashura (tenth day of Muharram) and is a day of mourning for Shiite Muslims. The killings at Karbala fueled the later Shiite movements. Anger at Husayn's death was turned into a rallying cry that helped undermine and ultimately overthrow the Umayyad Caliphate.