Regulæ Juris,[1] also spelled Regulae iuris (Latin for 'Rules of Law'), were legal maxims which served as jurisprudence in Roman law.
"[3] Jus novum (c. 1140-1563) Jus novissimum (c. 1563-1918) Jus codicis (1918-present) Other Sacraments Sacramentals Sacred places Sacred times Supra-diocesan/eparchal structures Particular churches Juridic persons Philosophy, theology, and fundamental theory of Catholic canon law Clerics Office Juridic and physical persons Associations of the faithful Pars dynamica (trial procedure) Canonization Election of the Roman Pontiff Academic degrees Journals and Professional Societies Faculties of canon law Canonists Institute of consecrated life Society of apostolic life In a specific sense, however, regulae juris are certain fundamental laws in the form of legal maxims memorialized in the Corpus Iuris Canonici, comprising 11 that Pope Gregory IX placed at the end of the fifth Book of Decretals and 88 that Pope Boniface VIII placed in the final title of Liber Sextus Decretalium.
These rules are deductions, rather than repetitions of legal principles in constitutions or judgments, of several laws on the same subject, and consequently were reserved to the final titles of the two books aforementioned, in imitation of the order of the Justinian Code, specifically the Digest, Liber l, Titulus 17.
While regulae juris are greatly important, few general principles are without some exception.
Some regulae juris are applicable in all matters and others only to judicial trials, benefices, et cetera; the following examples of those of limited applicability are from the Liber Sextus Decretalium: 88 legal dicta, axioms, or principles comprise the De Regulis Juris promulgated in 1298 by Pope Boniface VIII.