|Covid-19|Battle of Bathys Ryax: Emperor Basil I ("the Macedonian") sends a Byzantine expeditionary force, led by Christopher (Basil's brother-in-law), to Anatolia. He defeats the Paulicians, and eliminates the sect as a military power. Their leader, Chrysocheir, is captured and (later) beheaded. Many Paulicians are forcibly located, on orders of Basil in Thrace, to serve as a frontier force against the Bulgarians.
Battle of Hafrsfjord: The Norse chieftain Harald Fairhair wins a great naval victory at Hafrsfjord, outside Stavanger. He becomes (at age 18) the first king of Norway. Harald's conquests and taxation system leads many Viking chiefs and their followers to emigrate to the British Isles and (later) to Iceland.
Sancho III Mitarra (or Menditarra) becomes the founder and first 'king' of the independent Duchy of Gascony, with loose ties to the Frankish Kingdom.
May 18 – Louis II, after his successful campaign against the Saracens, is crowned for the second time as Roman Emperor ("Emperor of the Franks").
Al-Andalus: The city of Toledo rises up against Umayyad rule, due to ethnic tensions between recent converts, the muwalladun, and the Arab elite.
Autumn – The Great Heathen Army returns to Northumbria, to put down a rebellion at York. King Ecgberht I and his archbishop, Wulfhere, are expelled by the Northumbrians and flee to Mercia.
The Danes, led by Halfdan and Guthrum, establish a winter quarter at Torksey in the Kingdom of Lindsey (now part of Lincolnshire). King Burgred pays tribute (Danegeld) in return for 'peace'.
King Artgal of Strathclyde is slain, through the connivance of King Constantine I of Alba (modern Scotland) and his Viking allies. Artgal's son, Run, succeeds to the Strathclyde throne.
The Zanj Rebellion: The Zanj (black slaves from East Africa) defeat the Abbasid forces, led by caliphal regent Al-Muwaffaq (brother of caliph Al-Mu'tamid). Hostilities in Mesopotamia (Southern Iraq) will preoccupy Al-Muwaffaq, and the Zanj will remain on the offensive over the next several years.
In Egypt, the first hospital (bimaristan) is built in Cairo by the Abbasid governor, Ahmad ibn Tulun. Physician licensure becomes mandatory in the Abbasid Caliphate.
Fujiwara no Yoshifusa, Japanese regent (sesshō), dies at his native Kyoto, having ruled since 858. He is succeeded as head of the Fujiwara clan by his son Fujiwara no Mototsune.
December 14 – Pope Adrian II dies (at age 80), after a 5-year reign. He is succeeded by John VIII, as the 107th pope of Rome.
Abaoji, ruler (khagan) of the Khitan Empire (d. 926)
Al-Farabi, Muslim philosopher (approximate date)
Huo Yanwei, Chinese general (d. 928)
Ki no Tsurayuki, Japanese writer and poet (d. 945)
Pietro II Candiano, doge of Venice (approximate date)
December 14 – Adrian II, pope of Rome (b. 792)
Artgal, king of Strathclyde (Scotland)
Athanasius I, bishop of Naples (b. 830)
Cenn Fáelad hua Mugthigirn, king of Munster (Ireland)
Chrysocheir, leader of the Paulicians (or 878)
Fujiwara no Yoshifusa, Japanese regent (b. 804)
Ibrahim ibn Ya'qub al-Juzajani, Muslim hadith scholar
Ivar the Boneless, Viking chief (approximate date)
April 2 – Muflih al-Turki, Abbasid general
Sargis, patriarch of the Church of the East
Zhang Yichao, general of the Tang Dynasty
Zhang Yunshen, general of the Tang Dynasty (b. 785)
Year 872 (DCCCLXXII) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar.