842

Europe

 * - and  sign a treaty.
 * — alliance of and  against emperor  — sworn and recorded in  languages.
 * succeeds as king of.
 * is succeeded by, then.
 * marries.

Byzantine Empire

 * Three year old succeeds  as emperor of.

Asia

 * End of the reign of caliph.
 * leave the Mongolian plateau.

Deaths

 * —, Abbasid caliph (b. )
 * of Japan (b. )
 * (b. )
 * , (b. )
 * , Chinese poet, philosopher, and essayist (born )