From Infogalactic: the planetary knowledge core
|Centuries:||8th century – 9th century – 10th century|
|Decades:||780s 790s 800s – 810s – 820s 830s 840s|
|Years:||811 812 813 – 814 – 815 816 817|
|814 by topic|
|State leaders – Sovereign states|
|Birth and death categories|
|Births – Deaths|
|Establishment and disestablishment categories|
|Establishments – Disestablishments|
|Ab urbe condita||1567|
|Chinese calendar||癸巳年 (Water Snake)
3510 or 3450
— to —
甲午年 (Wood Horse)
3511 or 3451
|- Vikram Samvat||870–871|
|- Shaka Samvat||736–737|
|- Kali Yuga||3915–3916|
|Japanese calendar||Kōnin 5
|Minguo calendar||1098 before ROC
|Seleucid era||1125/1126 AG|
|Thai solar calendar||1356–1357|
- Byzantine–Bulgarian Wars: Krum, ruler (khan) of the Bulgarian Empire, assembles a huge army (including Slavs and Avars) for a campaign against the Byzantine Empire. He dies of a stroke before he sets out for a major attack on Constantinople. Krum is succeeded by his son Omurtag.
- January 28 – Charlemagne dies of pleurisy in Aachen after a 13-year reign as the first Holy Roman Emperor. He is embalmed and buried in Aachen Cathedral. Charlemagne is succeeded by his son Louis the Pious as king of the Frankish Empire.
- Louis I establishes himself at the imperial court of Aachen. He appoints Benedict of Aniane as his chief advisor on religious matters and makes him abbot of Kornelimünster Abbey which is founded by him.
- Shinsen Shōjiroku, a record of the genealogy of the ancient Japanese noble families, is completed during the reign of emperor Saga.
- Byzantine Iconoclasm: Conflict erupts between emperor Leo V and patriarch Nikephorus on the subject of iconoclasm. The later is deposed and Nikephorus excommunicates Leo.
- Abd-Allah ibn Numayr, Muslim narrator of hadith
- Abu Nuwas, Muslim poet (b. 756)
- February 18 – Angilbert, Frankish diplomat and abbot
- Baizhang Huaihai, Chinese Zen Buddhist monk (b. 720)
- January 28 – Charlemagne, king and emperor of the Franks
- Gruffydd ap Cyngen, Welsh prince (approximate date)
- April 13 – Krum, ruler (khan) of the Bulgarian Empire
- Li Jifu, chancellor of the Tang Dynasty (b. 758)
- Odo of Metz, Frankish architect (b. 742)
- Waldo of Reichenau, Frankish abbot and bishop
- William of Gellone, Frankish nobleman (or 812)
- Wu Shaoyang, general of the Tang Dynasty
- John V.A. Fine, Jr. (1991). The Early Medieval Balkans: A Critical Survey from the Sixth to the Late Twelfth Century, p. 99. ISBN 978-0-472-08149-3