Liber Extra
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.