Despite its non-Christian origins, the scheme of the cardinal virtues (prudence, justice, fortitude, and temperance) found wide acceptance in medieval theology, philosophy, and religious literature. The present study is the first to investigate the history of the four virtues in the Latin Middle Ages from patristic times to the late fourteenth century. It examines the position of the cardinal virtues between religious and secularized conceptions of morality and attempts to reveal some distinctly Christian aspects of medieval virtue theory notwithstanding its manifest indebtedness to ancient ethics. Exploring learned and popularizing sources alike, including much unedited material, this study covers a broad spectrum of moral debate during ten centuries of Western intellectual history.