The research project is located at a central interface between art history, book history, and the study of material religion. By focusing on the ornament of medieval books as a material practice, the aim of this project is to remove barriers that have stood in the way of a new understanding of the arts of the medieval book. Instead of the traditional contrast between material and representation, as well as text and illustration, the focus turns to a new holistic concept of ornament described by the medieval Latin terms “ornamentum”, “ornatus”, and “decorum”. Used in this sense, ornament is always related to what it embellishes; it presupposes an action of decoration that is executed on or around objects and persons. The research project will explore this relational nature of ornament in medieval manuscripts, thereby creating a new model for thinking about ornament and its role in material religion in a general sense.