891

By place

Europe

• February 21 - Guy III, duke of Spoleto, is crowned Holy Roman Emperor by Pope Stephen V. His son Lambert is proclaimed king of Italy, at the capital of Pavia in Lombardy.
• Summer - Orso, Lombard prince of Benevento, is deposed after the capture of Benevento by the Byzantines. Benevento becomes the capital of the thema of Longobardia.
• Battle of Leuven: Viking raiders on the Dyle River, in modern-day Belgium, suffer a crushing defeat by Frankish forces under King Arnulf of Carinthia.

Emirate of Córdoba

• Muslim forces led by Abdullah ibn Muhammad al-Umawi, Umayyad emir of Córdoba, defeat the rebel leader Umar ibn Hafsun at Poley, in Al-Andalus.

Arabian Empire (Caliphate)

• June 2 - Al-Muwaffaq, an Abbasid prince and Commander-in-chief, dies at the capital of Baghdad. His son Al-Mu'tadid is recognized as regent, and second heir of the Abbasid Caliphate.

Japan

• February 25 - Fujiwara no Mototsune, a Japanese statesman, dies. In his lifetime, he had forced the resignation of Emperor Yōzei and become head of the Fujiwara clan.

By topic

Religion

• September 14 - Pope Stephen V dies after a 6-year reign. He is succeeded by Formosus, former cardinal bishop of Portus, as the 111th pope of the Catholic Church.