Decades: 770s 780s 790s 800s 810s - 820s - 830s 840s 850s 860s 870s

Years: 820 821 822 823 824 - 825 - 826 827 828 829 830

• Egbert of Wessex defeats Beornwulf of Mercia at Ellandun. Kent, Surrey, Sussex and Essex submit to Wessex and East Anglia acknowledges Egbert as overlord.
• Emperor Louis the Pious of the Franks wars against the Wends and Sorbs.

• Louis II, emperor