Battle of Berzitia: The Bulgarian ruler (khagan) Telerig sends a small raiding army (12,000 men) to strike into the southwest of Macedonia, and capture Berzitia. Emperor Constantine V is informed about this raid by his spies in Pliska, and assembles an enormous force (80,000 men). He surprises the Bulgarians, who did not expect to find a Byzantine army there, and defeats them decisively. The Bulgars suffer heavy losses.
Telerig sends a message to Constantine V, stating that he is going to flee in exile to Constantinople. In exchange, he asks the emperor to reveal the spies to his associates in Pliska for their own safety. Constantine sends the Bulgarian government a list of the spies; however, Telerig executes them all, and eliminates the Byzantine spy network within his government.
Saxon Wars: Saxon raiders ravage much of northern Hesse (modern Germany), and burn the abbey at Fritzlar, putting the abbot and monks to the sword. Charlemagne hurriedly returns to Austrasia, assembles local troops, and recaptures Eresburg, before the approach of winter halts further operations.
King Aurelius dies after a 6-year reign, and is succeeded by his cousin-in-law Silo, as ruler of Asturias (Northern Spain).
Britain
Unrest in the Northumbrian Church appears to lead to the expulsion of King Alhred, who is driven from his capital York. He sails from Bamburgh into exile amongst the Picts, where he is received by King Ciniod I. He is replaced by Æthelred I, the 11-year-old son of the late king Æthelwald Moll.
A 1.2% growth of 14 C concentration recorded in tree rings, along with corresponding spikes of 36 Cl and 10 Be recorded in ice cores, suggests that a very strong solar storm may have hit Earth in either 774 or 775.
↑Fine, John V. A. Jr. (1991) [1983]. The Early Medieval Balkans: A Critical Survey from the Sixth to the Late Twelfth Century. Ann Arbor: University of Michigan Press. p.77. ISBN0-472-08149-7.