I just finished reading Historia Brittonum (History of the Britons) by Nennius, translated in the 19th century by J. A. Giles. This early history of the British Isles is usually attributed to Nennius, a Welsh monk, and was possibly first compiled around 830 AD. There are a number of old manuscripts of this work that differ from one another to varying degrees. Modern scholarship suggests the work may be a compilation of multiple anonymous authors, with various additions throughout the century.
There is much myth and legend intertwined with some factual history. It begins with the creation of the world and goes all the way through the Roman conquest of Britain and the subsequent Saxon invasions. There is a fairly long passage dealing with King Arthur and his battles against the Saxon armies.
This history reveals a picture of how Britains likely thought of themselves in the early middle ages.
“For it is better to drink a wholesome draught of truth from the humble vessel, than poison mixed with honey from a golden goblet.”