The history of the medieval Church is, in many ways, the history of its norms. Across more than a millennium, councils gathered bishops, abbots, theologians, and occasionally secular rulers to deliberate on matters of doctrine, discipline, and governance. The canons they produced-concise, authoritative statements intended to regulate belief and behavior-became some of the most influential texts in the shaping of Western Christianity. They were not merely rules; they were instruments through which the Church articulated who it was, what it valued, and how it understood its place in the world. This book begins from the premise that conciliar canons were central to the construction of ecclesiastical identity in the Middle Ages, and that their study offers a privileged window into the evolving self-understanding of the Christian community.