Al-Hurr ibn Yazid al-Tamimi al-Riyahi commanded the Kufan vanguard sent by Ibn Ziyad to halt Husayn. On Ashura he switched sides to join Husayn and was martyred on 10 Muharram 61 AH (680). His shrine lies ~7 km west of Karbala; its dome was built by the Safavid Shah Ismail I. The grave site rests on tradition. (Sources: WikiShia; Wikipedia.)