al-Ḥusayn ibn ʿAlī
Abū ʿAbd Allāh · Sayyid shabāb ahl al-janna, al-Shahīd (the Martyr), Sayyid al-Shuhadāʾ (in Shīʿī tradition)
Younger grandson of the Prophet ﷺ, third son of ʿAlī and Fāṭima. Famous for his piety. Refused to give bayʿa to Yazīd ibn Muʿāwiya in 60 AH and travelled towards Kūfa with his family at the invitation of its people, who then betrayed him. Surrounded by Yazīd's army at Karbalāʾ on the banks of the Euphrates and martyred along with most of his male family on 10 Muḥarram 61 AH / 680 CE — the foundational tragedy of the Shīʿa and a profound mourning event in all Muslim traditions. Ancestor of the Husaynid line — including Imām ʿAlī Zayn al-ʿĀbidīn and through him the Twelve Imāms (in Shīʿī tradition), Zaydīs, Faṭimid caliphs, and many Sayyid lines.