Ammar ibn Yasir was one of the earliest Muslims and a close companion of the Prophet; his mother Sumayya was the first female martyr of Islam. Though over ninety, he was martyred fighting in Ali's ranks at the Battle of Siffin (37/657) and buried near Raqqa. The Uwais al-Qarni Mosque and shrine over his grave was destroyed with explosives by ISIS in 2013-2014 and has not been rebuilt. (Sources: TDV 'Ammâr b. Yâsir'; Wikipedia.)