839Centuries: 8th century - 9th century - 10th century
- Louis the Pious attempts to divide his empire among his sons.
- Ethelwulf succeeds Egbert as king of Wessex.
- Uen is succeeded by Uurad as king of the Picts
- Beginning of the reign of Alpin II of Dalriada. (approximate date)
- Michael III, Byzantine Emperor