839

Births 
 Charles the Fat of France is born.

 Deaths 

 Áed mac Boanta, king of Dál Riata
 Aznar I, king of Aragon
 Cathal mac Muirgiussa, king of Connacht
 Chengguan, Chinese Buddhist monk (b. 738)
 Cummascach mac Congalaig, king of Brega
 Egbert, king of Wessex
 Eóganan mac Óengusa, king of the Picts
 Ibrahim ibn al-Mahdi, Muslim prince (b. 779)
 Muhammad at-Taqi, Muslim ninth Ismā'īlī imam (or 840)
 Muiredach mac Eochada, king of Ulaid
 Pei Du, chancellor of the Tang Dynasty (b. 765)
 Rorgon I, count of Maine (or 840)
 Sicard, prince of Benevento
 Vache, prince of Kakheti
 Wiglaf, king of Mercia