806

Year 806 (DCCCVI) was a common year starting on Thursday of the Julian calendar, the 806th year of the Common Era (CE) and Anno Domini (AD) designations, the 806th year of the 1st millennium, the 6th year of the 9th century, and the 7th year of the 800s decade.

Events

February 5 – Emperor Kanmu dies after a 25-year reign, that has seen Korean culture and technology introduced to Japan. He is succeeded by his son Heizei, as the 51st emperor of Japan.<ref name="kunaichō">Emperor Heizei, Yamamomo Imperial Mausoleum, Imperial Household Agency</ref>
Hōzen-ji Temple is founded in Wakakusa, Nakakoma District, Japan (now Minami-Alps, Yamanashi Prefecture). The temple follows the Shingon sect of Japanese Buddhism.

Arab–Byzantine wars: Caliph Harun al-Rashid leads a huge military expedition, assembling men from Syria, Palestine, Persia, and Egypt. The invasion army (reportedly 135,000 men) departs from Raqqa, residence of Harun, and enters Cappadocia through the Cilician Gates, sacking several Byzantine fortresses and cities. Heraclea is captured after a month-long siege (August/September). The city is plundered and razed; its inhabitants are enslaved and deported to the Abbasid Caliphate.Template:Sfn Template:Sfn

Arab–Byzantine wars: An Abbasid fleet under Humayd ibn Ma'yuf al-Hajuri raids Cyprus, carrying off 16,000 inhabitants as slaves.Template:Sfn
Harun al-Rashid appoints Ashot Msaker ("the Carnivorous") as the new presiding prince of Armenia. The Bagratids emerge as one of the country's two most powerful noble families. Harun recognizes another Bagratid branch, under Ashot I Curopalates, as princes of Caucasian Iberia.<ref>Template:Cite book</ref><ref>Template:The Making of Byzantium, 600–1025</ref>
Rafi ibn al-Layth, an Arab nobleman, leads a large-scale rebellion against oppressive taxation by the Abbasid governor Ali ibn Isa ibn Mahan. He launches a revolt in Samarkand, which spreads quickly across Khorasan.

Vikings massacre Columba's monks, and all the inhabitants on the island of Iona (Scotland). Other monks flee to safety in the monastery of Kells (Ireland). They take with them the Book of Kells.
King Eardwulf of Northumbria is expelled from his kingdom by his rival Ælfwald II, who takes the throne. Eardwulf flees to the Frankish court of Charlemagne, and later visits Pope Leo III in Rome.

November – Al-Hakam I, Umayyad emir of Córdoba, reasserts his control over the city of Toledo, autonomous since 797. To this effect Al-Hakam has over 72 nobles (accounts talk of 5,000) massacred at a banquet, crucified and displayed along the banks of the Guadalquivir River (modern Spain), in what comes to be known as the "Day of the Trench".Template:Sfn
Emperor Charlemagne divides the Frankish Empire under his three sons, called Divisio Regnorum. For Charles the Younger he designates the imperial title, Austrasia and Neustria, Saxony, Burgundy, and Thuringia. To Pepin he gives Italy, Bavaria, and Swabia. His youngest son Louis the Pious receives Aquitaine, the Spanish March, and Provence.
Grimoald III, Lombard duke of Benevento, dies without heirs. He is succeeded by Grimoald IV, who is forced to pay tribute to King Charles the Younger.