830

Centuries: 8th century - 9th century - 10th century

Decades: 780s 790s 800s 810s 820s - 830s - 840s 850s 860s 870s 880s

Years: 825 826 827 828 829 - 830 - 831 832 833 834 835

• Christian missionary Ansgar visits Birka, trade city of the Swedes.
• Earliest date of composition for the Historia Brittonum, attributed to Nennius, and known for its list of 12 battles of King Arthur.
• Egbert of Wessex defeats the Welsh.
• Al-Khwarizmi writes the Hisab 'al-jabr' w?al-muqabala, an important work on algebra.
• Borobodur[?] is completed as a Buddhist monument, after about 50 years of work.

Births

• Emperor Koko of Japan
• Carloman, King of Bavaria

Deaths

• Saint Glastian[?], mediator between Scots and Picts