820
From Freepedia
| Years: 816 817 818 819 - 820 - 821 822 823 824 | |
| Decades: 790s 800s 810s - 820s - 830s 840s 850s | |
| Centuries: 8th century - 9th century - 10th century | |
Events
- Persian scientist Khwarizmi founded algebra.
- Michael II succeeds Leo V as Byzantine Emperor
- The Historia Brittonum is written (approximate date)
- Feidlimid mac Cremthanin assumes the Kingship of Munster
Births
- Rhodri Mawr ('the Great'), ruler of Gwynedd (Wales) (approximate date) (d. 878)
- Photius I, Patriarch of Constantinople (approximate date) (d. 891)
Deaths
- December 24 - Leo V, Byzantine Emperor (b. 775)(assassinated)
- Tang Xian Zong, emperor of China (end of reign)



