Called toward Kūfah by pledges its people could not keep, al-Ḥusayn ibn ʿAlī was intercepted in the plain of Karbalāʾ by an Umayyad army and cut off from the Euphrates. On 10 Muḥarram 61 — the day of ʿĀshūrāʾ — after refusing allegiance to Yazīd, he was killed together with some seventy of his family and companions, and the women and children of the Prophet's ﷺ house were marched to Damascus.
Sunni historiography has never disputed the horror: the classical chroniclers record the day as an atrocity and count al-Ḥusayn the master of the youth of Paradise, martyred. The commemorative forms built upon the day differ across traditions; the event itself belongs to the whole community's memory.
Date and day are among the most firmly transmitted of the first century.