813

813 in various calendars
Gregorian calendar	813; DCCCXIII
Ab urbe condita	1566
Armenian calendar	262; ԹՎ ՄԿԲ
Assyrian calendar	5563
Balinese saka calendar	734–735
Bengali calendar	220
Berber calendar	1763
Buddhist calendar	1357
Burmese calendar	175
Byzantine calendar	6321–6322
Chinese calendar	壬辰年 (Water Dragon); 3510 or 3303; — to —; 癸巳年 (Water Snake); 3511 or 3304
Coptic calendar	529–530
Discordian calendar	1979
Ethiopian calendar	805–806
Hebrew calendar	4573–4574
Hindu calendars
- Vikram Samvat	869–870
- Shaka Samvat	734–735
- Kali Yuga	3913–3914
Holocene calendar	10813
Iranian calendar	191–192
Islamic calendar	197–198
Japanese calendar	Kōnin 4; (弘仁４年)
Javanese calendar	709–710
Julian calendar	813; DCCCXIII
Korean calendar	3146
Minguo calendar	1099 before ROC; 民前1099年
Nanakshahi calendar	−655
Seleucid era	1124/1125 AG
Thai solar calendar	1355–1356
Tibetan calendar	阳水龙年; (male Water-Dragon); 939 or 558 or −214; — to —; 阴水蛇年; (female Water-Snake); 940 or 559 or −213

Millennium:	1st millennium
Centuries:	8th century; 9th century ; 10th century;
Decades:	790s; 800s; 810s ; 820s; 830s;
Years:	810; 811; 812; 813 ; 814; 815; 816;

Year 813 (DCCCXIII) was a common year starting on Saturday (link will display the full calendar) of the Julian calendar.

"813" may also refer to a duology of novels by Maurice Leblanc, starring his gentleman thief Arsène Lupin.

Events

June 22 – Battle of Versinikia: The Bulgars led by Krum, ruler (khan) of the Bulgarian Empire, defeat emperor Michael I near Edrine (modern Turkey). The Byzantine army (26,000 men) is destroyed by an counter-attack of Bulgarian heavy cavalry while trapped in the valley. Krum captures the Byzantine camp and a rich prize including gold and weaponry.
July 11 – Michael I, under threat by conspiracies, abdicates in favor of his general Leo the Armenian and becomes a monk (under the name Athanasius). His sons are castrated to prevent them succeeding the Byzantine throne, and relegated into monasteries. One of them, Niketas (renamed Ignatius), eventually becoming a patriarch of Constantinople.
Ashot I becomes the first Georgian Bagratid prince of Iberia under the Byzantine protection.

Louis the Pious is crowned co-emperor of the Franks with his father Charlemagne.
The Bulgars capture Adrianople.
Forces from today's Denmark attack today's Vestfold due to insubordination.

Fourth Fitna: The Siege of Baghdad ends with the fall of the city and the death of al-Amin, making al-Mamun the undisputed Abbasid caliph.
The Baghdad School of Astronomy is opened by al-Mamun.

Third Council of Tours: Priests are ordered to preach in the vernacular (either Vulgar Latin or German).