 He borrowed from them the order of the subject-matter, the division 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 antiquæ", 191 are from Gregory IX himself, seven from decretals of Innocent III not inserted in the former collections, and two are 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.