821
| Years: 817 818 819 820 - 821 - 822 823 824 825 | |
| Decades: 790s 800s 810s - 820s - 830s 840s 850s | |
| Centuries: 8th century - 9th century - 10th century | |
Events
- Tang Mu Zong becomes emperor of China
Deaths
- February 11 - Benedict of Aniane, monastic founder and saint
- December 18 - Theodulf, Bishop of Orléans
- Coenwulf, king of Mercia