797 CE

Or August 19 – Empress Irene organizes a conspiracy against her son Constantine VI. He is captured and blinded; Irene exiles him to Principo, where he dies shortly thereafter of his wounds. Irene begins a 5-year reign, and calls herself basileus ("emperor") of the Byzantine Empire. (Sources and historians conflict on whether this was in April or August.). Battle of Rhuddlan: Welsh forces, including those of Powys and Dyfed, clash with Mercians. King Coenwulf tries to re-assert his domination of northeast Wales. King Caradog ap Meirion of Gwynedd is killed during the fighting (approximate date). King Charlemagne issues the Capitulare Saxonicum, making Westphalian, Angrian and Eastphalian Saxons equal to other peoples in the Frankish Kingdom. The Nordalbian Saxons revolt; a Frankish fleet is sent to the North Sea coast of Germany. It lands in Hadeln, a marshy coastal region between the Weser and Elbe estuaries, near modern-day Cuxhaven. Charlemagne invades northern Saxony, and again accepts the submission of the Saxons.