Decretals, epistolae decretales, are papal letters that have a claim to universal validity and clarify questions of Church law. Already in Late Antiquity, petitioners would submit legal or disciplinary questions to the Roman emperor, who in response would provide authoritative answers in imperial rescripts. Papal decretal law was the product of an analogous procedure. Private parties would ask the pope to adjudicate their disputes, and in response the pope would set forth authoritative answers in decretal letters. The oldest fully preserved papal decretal is by Pope Siricius (384–99). Only with the pontificate of Alexander III (1159–81), however, did the number of decretals skyrocket and, as a result, there take place the further legal development and elaboration of the ius novum. Just two generations after Gratian’s Decretum (c. 1140), papal legislative acts had developed and changed canon law like never before.

The final chapter completes the analysis, weaving together themes from previous chapters to investigate how the canons were used. Beginning with the papal deployment of the conciliar authorities, the chapter suggests an inherent flexibility: while the papacy would reaffirm the conciliar decrees in some circumstances, in others it would use them merely as guidelines. The chapter then turns to local and episcopal use of the conciliar decrees, showing that in some cases bishops followed the stipulations, while elsewhere they attempted to avoid, change, or interpret them. Finally, the use of the decrees by canon lawyers, both in the schools and in episcopal retinues, is considered: immediately after the council, there was no one way in which these lawyers treated and understood the decrees, and it was only with Bernard of Pavia’s canonical collection known as the Breviarium Extravagantium (ca. 1191) that canon lawyers began to interpret them as overarching, general stipulations. Overall, the chapter points to the plurality of ways in which twelfth–century clerics conceived of papal and conciliar power and authority, with both conciliar decrees and papal decretals being viewed with uncertainty as they became established legal precedents.

This fourth chapter provides an extended discussion of the promulgation and surviving manuscript copies of the 1179 conciliar canons. It begins with an analysis of the methods by which the canons of papal councils were promulgated and transmitted between ca. 1050 and 1215, before briefly detailing the events of the 1179 Lateran Council as far as they can be reconstructed from surviving narrative accounts. The majority of the chapter, however, focusses on the dissemination and movement of the 1179 conciliar decrees, and what that can tell us about contemporary perceptions of papal conciliar canons. A key issue is the extent to which the decrees were transmitted as a coherent whole, and therefore viewed as a set of texts that had to be kept together without alteration. Overall, the chapter suggests that the 1179 canons initially existed in more than one recension but, more importantly, demonstrates that the versions that were received in different areas of Christendom were not necessarily the same. It therefore illustrates how uncertain the transmission of papal ‘legislation’ remained, late into the twelfth century.