Given the hurdles one faced in trying to stay healthy in later medieval England, it should come as no surprise that the medieval English placed a premium on competent medicine. As Carole Rawcliffe has argued, “medieval life was beset by constant threats to health arising from poor diet (at both ends of the social spectrum), low levels of hygiene, high rates of infant mortality, the risks of childbirth and repeated pregnancies, accidents and injuries.”1 Add to this the episodic dangers of war, epidemics, and famine, as well as the lack of antibiotics, and we have a world in great need of medical expertise. Because of the prohibitive cost of professional medicine, men and women in late medieval England insisted that medical practitioners be held to high standards. Swindlers and frauds who posed as physicians but had no real medical credentials felt the full wrath of medieval society. One of the best-known, and most revealing, cases is that of Roger Clerk of Wandsworth, indicted before the mayor’s court of London in May of 1382.