839
| Years: 835 836 837 838 - 839 - 840 841 842 843 | |
| Decades: 800s 810s 820s - 830s - 840s 850s 860s | |
| Centuries: 8th century - 9th century - 10th century | |
Events
- 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)
- Creation of the Balaton principality
- Michael III, Byzantine Emperor