Kazuo Ishiguro has suggested that his work of medieval fantasy, The Buried Giant (2015), draws on a “quasi-historical” King Arthur, in contrast to the Arthur of legend. This article reads Ishiguro’s novel against the medieval work that codified the notion of an historical King Arthur, Geoffrey of Monmouth’s History of the Kings of Britain (c. 1139). Geoffrey’s History offered a largely fictive account of the British past that became the most successful historiographical phenomenon of the English Middle Ages. The Buried Giant offers an interrogation of memory that calls such “useful” constructions of history into question. The novel deploys material deriving from Geoffrey’s work while laying bear its methodology; the two texts speak to each other in ways sometimes complementary, sometimes deconstructive. That Ishiguro’s critique can be applied to Geoffrey’s History points to recurrent strategies of history-making, past and present, whereby violence serves as a mechanism for the creation of historical form.