of Gratian. Some authors (Schulte, Launin) maintain that Gregory IX abrogated even those laws prior to Gratian's time that the latter had not included in his "Decretum", but others contest this opinion. Differences with modern codes The Decretals of Gregory IX differ widely from modern codes. Instead of containing in one concise statement a legislative decision, they generally start with an account of a controversy, the allegations of the parties in dispute, and a demand or the solution of the question; this species facti or the pars historica has no juridical value whatever. The enacting part of the chapter (pars dispositiva) alone has the force of law; it contains the solution of the case or the statement of the rule of conduct. The rubrics of the titles have the force of law when their sense is complete, as for instance, Ne sede vacante aliquid innovetur (Let there be no innovation while the see is vacant), because the headings form an integral part of the official code of the laws. However, they ought always to be interpreted according to the decisions contained in the chapters. Historical indications The historical indications concerning each chapter are often far from being exact, even since they were corrected in the Roman edition of 1582. It may be regretted that St. Raymond did not have recourse to the original documents themselves, of which a large number must have been at his disposal. The summaries (summaria) that precede the chapters are the work of the canonists, and may assist in the elucidation of the text. The partes decisae are sometimes of like use, but never when these parts were designedly omitted from a desire to extinguish their legal force or because they contain decisions irreconcilable with the actual text of the law. Glosses Like the former canonical collections, the Decretals of Gregory IX were soon glossed. It was customary to add to the manuscript copies textual explanations written between the lines (glossa interlinearis) and on the margin of the page (glossa marginalis). Explanations of the subject-matter were also added. The most ancient glossarist of the Decretals of Gregory IX is Vincent of Spain; then follow Godefridus de Trano (died 1245), Bonaguida Aretinus (thirteenth century) and Bernard of Botone or Parmensis (died 1263), the author of the "Glossa ordinaria", i.e., of that gloss to which authoritative credence was generally given. At a later date some extracts were added