|Covid-19|Summer – Emperor Basil I allies with the Frankish emperor Louis II against the Saracens. He sends a Byzantine fleet of 400 ships (according to the Annales Bertiniani), under the command of Admiral Nicetas, to support Louis (who is besieging the city port of Bari), and to clear the Adriatic Sea of Muslim raiders.
The Hagia Sophia in Constantinople suffers great damage during an earthquake, which makes the eastern half-dome collapse. Basil I orders the basilica (church) to be repaired.
August 8 – King Charles the Bald tries to take Lotharingia, kingdom of Lothair II, after the latter's death, but is resisted by his brother Louis the German.
The Danes, led by Viking chieftain Ivar the Boneless, 'make peace' with the Mercians (by accepting Danegeld). Ivar leaves Nottingham on horseback, and returns to York.
Autumn –The Great Heathen Army, led by Ivar the Boneless and Ubba, invades East Anglia, and plunders Peterborough. The Vikings take up winter quarters at Thetford.
November 20 – King Edmund the Martyr and his East Anglian army are destroyed by the Vikings. He is captured, tortured, beaten and used as archery practice.
The Zanj Rebellion: The Zanj (black slaves from East Africa), provoked by mercilessly harsh labor conditions in salt flats, and on the sugar and cotton plantations of southwestern Persia, revolt.
Summer – Caliph Al-Mu'tazz is murdered by mutinous Muslim troops, after a 3-year reign. He is succeeded by Al-Muhtadi (a grandson of former Al-Mu'tasim), as ruler of the Abbasid Caliphate.
May 26 – An earthquake and tsunami devastate a large part of the Sanriku coast, on the northeastern side of the island of Honshu.
Stela 11, the last monument ever erected at Tikal, is dedicated by ruler (ajaw) Jasaw Chan K'awiil II.
The Fourth Council of Constantinople is called by Basil I and Pope Adrian II. The council condemnes Photius I, and deposes him as patriarch. His predecessor Ignatius is reinstated.
January 2 – Yōzei, emperor of Japan (d. 949)
Gung Ye, king of Hu Goguryeo (approximate date)
Muhammad al-Mahdi, Muslim Twelver Shī‘ah Imām
February 14 – Cyril, Byzantine missionary and bishop
August 8 – Lothair II, king of Lotharingia (b. 835)
September 8 – Ahmad ibn Isra'il al-Anbari, Muslim vizier
September 18 – Wenilo, Frankish archbishop
October 14 – Pang Xun, Chinese rebel leader
November 20 – Edmund the Martyr, king of East Anglia
Al-Darimi, Muslim scholar and imam
Al-Hakim al-Tirmidhi, Muslim jurist (approximate date)
Al-Jahiz, Afro-Muslim scholar and writer (or 868)
Al-Mu'tazz, Muslim caliph (b. 847)
Dongshan Liangjie, Chinese Buddhist teacher (b. 807)
Dúnlaing mac Muiredaig, king of Leinster (Ireland)
Ermentrude of Orléans, queen of the Franks (b. 823)
Gundachar, count (or margrave) of Carinthia
Leuthard II, Frankish count (or 858)
Rothad of Soissons, Frankish bishop
Shapur ibn Sahl, Persian physician
Solomon, Frankish count (approximate date)
Yu Xuanji, Chinese poet (or 868)
Year 869 (DCCCLXIX) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar.