Sexuality in modern western culture is central to identity but the tendency to define by sexuality does not apply to the premodern past. Before the 'invention' of sexuality, erotic acts and desires were comprehended as species of sin, expressions of idealised love, courtship, and marriage, or components of intimacies between men or women, not as outworkings of an innermost self. With a focus on c. 1100–c. 1800, this book explores the shifting meanings, languages, and practices of western sex. It is the first study to combine the medieval and early modern to rethink this time of sex before sexuality, where same-sex and opposite-sex desire and eroticism bore but faint traces of what moderns came to call heterosexuality, homosexuality, lesbianism, and pornography. This volume aims to contribute to contemporary historical theory through paying attention to the particularity of premodern sexual cultures. Phillips and Reay argue that students of premodern sex will be blocked in their understanding if they use terms and concepts applicable to sexuality since the late nineteenth century, and modern commentators will never know their subject without a deeper comprehension of sex's history.