This project explores the interaction of religious and philosophical ways of thinking about ethics in 13th-century France, with particular attention to the pseudo-Vincent of Beauvais Speculum morale, an influential but hitherto unstudied ethical encyclopaedia. Employing text similarity detection software to assist in exploring how this work transforms its literary sources, it considers how ethical ideas were adapted and diffused in response to on-going debates about behaviour and ethical standards in society. It will lead to a jointly authored volume on the Speculum situating the work in relation to broader controversies raised by Aristotelian thought, as well as an annotated online edition of the Speculum.