Discordia in Concordia: The Two-Step Development of the Post-Gratian Gloss and the Emergence of a New Era in Canon Law

Around 1140, a canon lawyer named Gratian published a legal collection titled Concordia Discordantium Canonum (“A Harmony of Discordant Canons”), which attempted to compile and reconcile the Church’s often contradictory laws. Because of its cohesiveness, comprehensiveness, and directness, canonists began using the Decretum (as it became called) as a textbook and legal reference; some canonists composed glosses to aid readers of this masterpiece. I argue that the glosses on Gratian’s Decretum developed over the course of two distinct subgenres—early glosses and late glosses. While early glosses were written to provide understanding of Gratian’s original legal arguments, late glosses were written to promote their authors’ own legal opinions. After surveying textual evidence for this two-step development, I consider why such a development occurred and make the case that temporal factors better explain the two-step development than geographic ones. By offering new explanations for the dramatic legal shifts of the twelfth century Church, this thesis offers new insight into one of the most dramatic legal revolutions of Roman Catholicism