|Covid-19|April 24 – Emperor Leo IV ("the Khazar") appoints his 5-year-old son Constantine VI co-ruler of the Byzantine Empire. This leads to an uprising of Leo's half-brothers, including Caesar Nikephoros, the second son of former emperor Constantine V. The revolt is quickly suppressed; Leo has the conspirators blinded, tonsured and exiled to Cherson (Southern Crimea) under guard.
King Charlemagne spends Easter in Treviso (Northern Italy), after putting down a rebellion in Friuli and Spoleto. He removes Hrodgaud of Friuli from power, and reforms the duchy as the March of Friuli (military frontier district). Co-conspirators who support the revolt are Arechis II, duke of Benevento, and Adalgis, son of former Lombard king Desiderius. Frankish counts are placed in the cities of Friuli.
Saxon Wars: The Saxons again revolt against Christianity and Frankish rule. Eresburg falls, but a Saxon assault upon the castle of Syburg (near Dortmund) fails. Charlemagne hurriedly returns from Italy, launching a counter-offensive which defeats the Saxons. Most of their leaders are summoned to the Lippe at the town of Bad Lippspringe (North Rhine-Westphalia), to submit formally to Charlemagne.
Battle of Otford: King Egbert II of Kent defeats the Mercians under King Offa (near Otford), and re-asserts himself as ruler of Kent.
Al-Jahiz, Afro-Muslim scholar and writer (d. 868)
Bai Xingjian, Chinese poet and writer (d. 826)
Lu Sui, chancellor of the Tang Dynasty (d. 835)
Sahnun ibn Sa'id, Muslim jurist (or 777)
Tahir ibn Husayn, Muslim governor (or 775)
Cellach mac Dúnchada, king of Leinster (Ireland)
Cináed Ciarrge mac Cathussaig, Dál nAraide king
Flaithniadh mac Congal, abbot of Clonfert
Hrodgaud, duke of Friuli (Italy)
Humayd ibn Qahtaba, Muslim military leader
Nuada ua Bolcain, abbot of Tuam (Ireland)
Year 776 (DCCLXXVI) was a leap year starting on Monday (link will display the full calendar) of the Julian calendar. The denomination 776 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.