"Geoffrey makes the Welsh Medraut into the villainous Modredus, but there is no trace of such a negative character for this figure in Welsh sources until the 16th century.There have been relatively few modern attempts to challenge the notion that the "Historia Regum Britanniae" is primarily Geoffrey's own work, with scholarly opinion often echoing William of Newburgh's late-12th-century comment that Geoffrey "made up" his narrative, perhaps through an "inordinate love of lying".