Decretals of Gregory IX
The Decretals of Gregory IX, also collectively called the Liber extra, are a source of medieval Catholic canon law. In 1230, Pope Gregory IX ordered his chaplain and confessor, Raymond of Penyafort, a Dominican, to form a new canonical collection destined to replace the Decretum Gratiani, which was the chief collection of legal writings for the church for over 90 years. It has been said that the pope used these letters to emphasize his power over the Universal Church.
Political circumstances
During Gregory's papacy, the church had established a prominent role in the temporal and spiritual affairs of Europe. Following his predecessor, Pope Honorius III, Gregory maintained papal supremacy. Nevertheless, the utility of a new collection was so evident that there may be no other motives than those the pope gives in the Bull Rex pacificus of 5 September 1234, viz., the inconvenience of referring to several collections containing decisions most diverse and sometimes contradictory, exhibiting in some cases gaps and in others tedious length; moreover, on several matters the law was uncertain.Work of St. Raymond
The Quinque compilationes antiquæ was a series of five of these collections of pontifical legislation from the Decretum Gratiani of Gratian to the pontificate of Honorius III. Raymond followed the method of the Quinque compilationes in compiling the new collection of canons, which he completed in about four years. He borrowed from the Quinque compilationes the order of the subject-matter, the division of the work into five books, of the books into titles, and of the titles into chapters. Of the 1971 chapters the Decretals of Gregory IX contain, 1771 are from the Quinque compilationes, 191 are from Gregory IX himself, seven from decretals of Innocent III not inserted in the former collections, and two of unknown origin. They are arranged, generally, according to the order of the ancient collections, i.e., each title opens with the chapters of the first collection, followed by those of the second, and so on in regular order. Next come those of Innocent III, and finally those of Gregory IX. Almost all the rubrics, or headings of the titles, have also been borrowed from these collections, but several have been modified as regards detail. This method considerably lightened St. Raymond's task.Editorial work
Pope Gregory IX's work involved the compilation of documents from former collections, modifying some decisions whilst discarding others. Additionally, Gregory omitted parts when he considered it prudent to do so, filled in the gaps, and cleared up doubtful points of the ancient ecclesiastical law by adding some new decretals to ensure his work was clear and concordant. He indicated by the words et infra the passages excised by him in the former collections. They are called partes decisae. The new compilation bore no special title, but was called "Decretales Gregorii IX" or sometimes "Compilatio sexta", i. e. the sixth collection with reference to the "Quinque compilationes antiquæ". It was also called "Collectio seu liber extra", i. e. the collection of the laws not contained in the "Decretum" of Gratian; hence the custom of denoting this collection by the letter X.Force of law
Image:Gregory IX bas-relief in the U.S. [House of Representatives chamber.jpg|thumb|275px|Gregory IX is portrayed among the great lawgivers of history by a bas-relief in the United States [House of Representatives|US House of Representatives chamber]]While the Liber Extra was neither formally designated as a code nor officially promulgated as such, many scholars nevertheless regard it as a de facto codification of canon law—or at minimum, as something approximating a codification very closely. There is scholarly disagreement about the precise legal authority of those decretals that were not incorporated into the Liber Extra. This debate is particularly pronounced concerning decretals dating from the period before Gratian's work. In contrast to the uncertainty surrounding earlier materials, the situation for decretal letters issued during the period between Gratian's compilation and 1234 is clearer. Gregory IX in Rex pacificus explicitly established that such decretals retained legal force only to the extent that they had been included in the new compilation and only in the form found there. Those not included ceased to have binding legal authority; the passages left out by Raimund However, in practice legal scholars continued to cite older collections, decretals not contained in the Liber Extra, and the partes decisae.