Carole Rawcliffe examines medieval attitudes to madness and the case of Henry VI. Mad kings are all the rage at present. The remarkable success, first of Alan Bennett’s stage play, The Madness of George III, and then of the widely acclaimed film version, has prompted a spate of newspaper articles and television programmes about the care of the mentally ill in eighteenth century Britain. George was not, however, the first English king to be diagnosed, albeit mistakenly, as insane. Nor was his mental collapse the first to trigger off a major constitutional crisis. Henry VI’s long incapacity from late July to December 1454 and his subsequent lapses in the spring and autumn of 1455 had even more dramatic consequences. Indeed, if, as seems likely, he never fully recovered what had at best been a rather tenuous hold on reality, his mental health might reasonably be described as the catalyst which sparked off the Wars of the Roses and enabled Edward IV to take the throne in 1461.