Battle of Karbala
The death of the Prophet's grandson defines Shia memory

The army of Umayyad caliph Yazid I massacred the small band of Husayn ibn Ali, grandson of the Prophet Muhammad, at Karbala. Husayn's death became a defining event for Shia Islam, deepened the Sunni–Shia split and is mourned every year on Ashura.
Wikipedia (Russian) · Wikipedia (English) · 7th century
Meanwhile around the world (±25 years)
Africa
- 698 Fall of Carthage and the Arab conquest of the Maghreb — 18 years later
- c. 700 The rise of the Kanem Empire — 20 years later
Alive at the time
- Pakal the Great (aged 77)
- Wu Zetian (aged 56)