Definition
A Latin phrase meaning "threefold right" or "tripartite law." In Roman law, the term refers specifically to the law of wills as it existed under Justinian, which derived its rules from three distinct sources: the praetorian edict, the civil law (jus civile), and the imperial constitutions. Justinian himself used the phrase to describe how the formal requirements for a valid Roman testament appeared to have a triple origin. The term thus captures both a structural observation about the sources of Roman testamentary law and a theoretical proposition about the nature of legal rights.
The maxim associated with the term — Jus triplex est, proprietatis, possessionis, et possibilitatis — extends the "threefold" concept into property theory, stating that right is threefold: of property, of possession, and of possibility. This formulation is distinct from the testamentary context but travels under the same Latin root and appears in the same dictionary entries.
Common Confusion
Two distinct legal propositions share the jus tripertitum / jus triplex label and are frequently run together in historical sources. The first is the testamentary doctrine: that Justinianic will law derived from three sources (praetorian edict, civil law, imperial constitutions). The second is the property maxim: that right itself is tripartite, consisting of property, possession, and possibility. These are not the same idea. Black's and Bouvier's both present them in sequence without clearly distinguishing them, which compounds the confusion. Researchers should identify which proposition a historical source is invoking before drawing any doctrinal conclusion.
Why It Matters in Research
This is a term of Roman law historical scholarship rather than operative Anglo-American doctrine. It appears in Law Mind corpus sources almost exclusively in the context of explaining the structure of Justinian's Institutes or in comparative discussions of testamentary formalities.
The primary research trap is treating the two distinct propositions — testamentary source-derivation and tripartite property rights — as interchangeable. They are not, and conflating them distorts any analysis of either.
Researchers working on the history of wills and succession will find jus tripertitum useful as a conceptual marker for the synthesis period of Roman law under Justinian, when older civil law requirements, praetorian modifications, and later imperial legislation were harmonized. Maine's Ancient Law (cited in both editions of Black's) is the key secondary source connecting this Roman doctrine to the common law tradition; that connection runs through equity's inheritance of praetorian flexibility, not through any direct reception of Roman testamentary form.
Researchers working on property theory will find the jus triplex maxim more relevant — it influenced later civilians and common lawyers who categorized rights in land. The distinction between property, possession, and possibility maps loosely onto fee simple, seisin, and contingent future interests in common law property discourse, though the correspondence is approximate and should not be over-read.
Historical sources written before the late nineteenth century may use jus tripertitum loosely to mean any threefold legal classification without referencing either the testamentary or the property-rights context specifically. Verify usage before relying on a citation.
Historical Dictionary Support
Black's (1st and 2nd editions) and Bouvier's agree on the core definition and all three cite the same Roman law source tradition, though only Bouvier's preserves the Latin passage from Sandars' Institutes of Justinian (Inst. 2.10.3), which is the primary text. Both editions of Black's cite Maine's Ancient Law for the observation about threefold derivation.
Where the sources diverge slightly: Bouvier's is more careful to present the term as Justinian's own characterization of the law of his time, framing it as a retrospective synthesis. Black's presents it more flatly as a descriptive name applied to Roman will law. The Bouvier framing is closer to the primary source and more useful for research purposes.
None of the three dictionary sources adequately separates the testamentary doctrine from the property maxim — they are run together in a single entry in each source. This is a genuine gap in the historical dictionary coverage that researchers must supply from context.
Jurisdictional Note
Jus tripertitum has no direct operative force in any common law jurisdiction. Its relevance is historical and comparative. Civil law jurisdictions with roots in Justinianic Roman law may encounter the concept in foundational texts, but it functions as a descriptive label for a historical synthesis, not as a continuing rule of decision.
Encyclopedia Cross-Reference
See: Roman Law; Wills and Testaments (Historical); Sources of Law