During the Middle Ages in Europe, some sexual and gendered behaviors were labeled “sodomitical” or evoked using ambiguous phrases such as the “unmentionable vice” or the “sin against nature.” How, though, did these categories enter the field of vision? How do you know a sodomite when you see one? Challenging the view that medieval ideas about sexual and gender dissidence were too confused to congeal into a coherent form, this book demonstrates that sodomy had a rich, multimedia presence in the period—and that a flexible approach to questions of terminology sheds new light on the many forms this presence took. Arguing that we need to take account of the role played by translation—whether visual, verbal, or cultural—in endowing sodomy with a pictorial or textual form, the book also considers the extent to which medieval materials can be re-visioned in light of twenty-first-century categories of thought. Also, the book advances discussion by showing how greater attention needs to be paid to motifs of gender slippage and to notions of imitation and derivation in medieval encounters with sex. Among the topics covered are depictions of the practices of sodomites in illuminated Bibles; motifs of gender transformation and sex change as envisioned by medieval artists and commentators on Ovid; sexual relations in religious houses and other enclosed spaces; and the applicability of modern categories such as “transgender,” “butch” and “femme,” “queer,” and “sexual orientation” to medieval culture.