History of the Britons (Historia Brittonum)

Although the origin of this book is much debated it remains, perhaps, one of the earliest recorded histories of Britain. It was believed that Nennius wrote the book around 796AD. If indeed he wrote this record, Nennius is recognised as being a teller, and embellisher, of historic characters and events.
This book remains notable however, as one of the earliest that mention Arthur (The King of Arthurian legend).