842

Events 
 February 14 – Charles the Bald and Louis the German sign a treaty.
 Oaths of Strasbourg — alliance of Louis the German and Charles the Bald against emperor Lothar — sworn and recorded in vernacular languages.
 Ramiro I succeeds Alfonso II as king of Asturias.
 Uurad is succeeded by Bred, then Ciniod.
 Charles the Bald marries Ermentrude.
 Three year old Michael III succeeds Theophilus (emperor) as emperor of Byzantium.
 End of the reign of caliph Moqtasim.
 Uyghurs leave the Mongolian plateau.

 Deaths 
 January 5 — Al-Mu'tasim, Abbasid caliph (b. 794)
 Emperor Saga of Japan (b. 786)
 Alfonso II of Asturias (b. 759)
 Theophilus, Byzantine Emperor (b. 813)
 Liu Yuxi, Chinese poet, philosopher, and essayist (born 772)