 Much of it is based on the "Historia Britonum", a 9th-century Welsh-Latin historical compilation, Bede's "Ecclesiastical History of the English People", and Gildas's 6th-century polemic "De Excidio et Conquestu Britanniae", expanded with material from bardic oral tradition and genealogical tracts, and embellished by Geoffrey's own imagination.In an exchange of manuscript material for their own histories, Robert of Torigny gave Henry of Huntingdon a copy of "History", which both Robert and Henry used uncritically as authentic history and subsequently used in their own works, by which means some of Geoffrey's fictions became embedded in popular history.