The outbreak of syphilis in Europe elicited a variety of responses concerning the disease's origins and cure. In this essay, I examine the theory of the origins of syphilis advanced by the 16th-century Italian surgeon Leonardo Fioravanti. According to Fioravanti, syphilis was not new but had always existed, although it was unknown to the ancients. The syphilis epidemic, he argued, was caused by cannibalism among the French and Italian armies during the siege of Naples in 1494. Fioravanti's strange and novel theory is connected with his view of disease as corruption of the body caused by eating improper foods. His theory of bodily pollution, a metaphor for the corruption of society, coincided with Counter-Reformation concepts about sin and the social order.