Nennius

Nennius, the name adopted by the author of Historia Britonum, a work which gives a mythical account of the Britons, the coming of the Romans, Vortigern and the Saxons, and the 12 victories of King Arthur. The work is not of great value except for fragments of earlier authors embodied in it, and the authorship is sometimes attributed to Gildas or some person unknown. The original was probably in ancient Welsh.