In an exchange of manuscript material for their own histories, Robert of Torigny gave Henry of Huntington a copy of "Historia Regum Britanniae", 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. The history of Geoffrey forms the basis for much British lore and literature as well as being a rich source of material for Welsh bards. It became tremendously popular during the High Middle Ages, revolutionising views of British history before and during the Anglo-Saxon period despite the criticism of such writers as William of Newburgh and Gerald of Wales. The prophecies of Merlin in particular were often drawn on in later periods, for instance by both sides in the issue of English influence over Scotland under Edward I and his successors.