My dissertation examines the crucifixion images found in four gospel manuscripts made in ninth–tenth century Brittany. The study derives from the recognition of a pattern in pictorial representations of the cross, in which the cross is characterized within an image as a physical, material thing. I describe this pattern as an intersection of media and an intersection of pictorial and liturgical space. I investigate the materialized cross as it functions within images, and the nature of those images as they function within their codices. I argue that a visual language developed in the early Middle Ages to articulate the instrumental role of material artwork. The instrumental cross is a gateway to understanding the presentation of other manufactured objects (such as books) in this vein. I characterize early medieval manuscripts as both liturgical/devotional spaces and active ritual objects. Examining the relationship between crosses and books illuminates the early medieval conception of manuscripts' function along with their visual arguments. I present complex manuscripts that have long lain below the art historical radar, discussing little-known material together with prominent examples in order to broaden our perspective on the early medieval field.