|Covid-19|King Beornwulf of Mercia invades East Anglia, but is killed in battle. He is succeeded by Ludeca, as ruler of Mercia.
Prince Aethelwulf, a son of King Egbert of Wessex, invades Kent, and drives out its pro-Mercian king Baldred.
May – Euphemius, Byzantine admiral, organises an uprising in Sicily against Emperor Michael II. He proclaims himself king (with the title of basileus) in Syracuse, independent from Constantinople. In turn, Euphemius is defeated by Byzantine troops (reinforcements from the East), and is driven out to North Africa.
King Harald Klak of Denmark receives the Frisian county of Rüstringen, as a gift from Emperor Louis the Pious.
Harald Klak accepts Christianity, and is baptized with his wife and son Godfrid at Mainz.
January 22 – Montuku, emperor of Japan (d. 858)
Al-Mubarrad, Muslim grammarian (d. 898)
Ansgarde of Burgundy, Frankish queen (approximate date)
Cyril, Byzantine missionary and bishop (d. 885)
Doseon, Korean Buddhist monk (d. 898)
Thābit ibn Qurra, Muslim astronomer and physician (d. 901)
William of Septimania, Frankish nobleman (d. 850)
Ashot I, prince of Iberia (or 830)
Ashot Msaker, prince of Armenia
Bai Xingjian, Chinese poet and writer (b. 776)
Beornwulf, king of Mercia
Fujiwara no Fuyutsugu, Japanese general (b. 775)
Heondeok, king of Silla (Korea)
Li Guangyan, Chinese general (b. 761)
Li Wu, prince of the Tang Dynasty
Theodore the Studite, Byzantine abbot (b. 759)
Wu Yantong, Chinese Buddhist monk
Zhu Kerong, Chinese governor (jiedushi)
Year 826 (DCCCXXVI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar.