Definition
A Latin legal term from old English law meaning imprisonment. The term denotes the condition or act of confining a person, understood in the historical common law tradition as a compound wrong consisting of two distinct elements: an unlawful taking (unjust apprehension) and an unlawful detention, whether the person was held in chains, in the stocks, or subjected to any other form of physical restraint, greater or lesser.
The term is principally encountered in medieval and early modern legal texts written in Law Latin, where it appears in treatises addressing the wrongs done to persons through physical confinement. Its significance lies not merely as a label for confinement but as a structured legal concept that disaggregates the act of imprisonment into its constituent offenses.
Common Confusion
IMPRISONAMENTUM should not be confused with its anglicized descendant, imprisonment, which in modern usage is a general descriptor for custodial confinement following conviction or pending trial. The Latin term carries a narrower, analytically precise meaning embedded in the common law of personal wrongs: it presupposes that the confinement is injusta — unlawful — making the term inherently tied to the concept of wrongful restraint rather than lawful custody. Modern uses of "imprisonment" can describe lawful state-sanctioned confinement; IMPRISONAMENTUM, as deployed in the sources, contemplates only the wrongful variety.
Core Elements
The definition drawn from Fleta identifies IMPRISONAMENTUM as duplex delictum — a double wrong:
1. INJUSTA CAPTIO: Unjust or unlawful taking. The initial act of seizing or apprehending the person without lawful authority.
2. INJUSTA DETENTIO: Unjust or unlawful detention. The continued holding of the person after seizure, whether in chains, in the stocks, or under any other form of restraint, minor or severe.
Both elements must be present for the full wrong to constitute imprisonamentum in the sense contemplated by Fleta. The formulation anticipates later common law thinking on false imprisonment, which similarly requires both an act of restraint and an absence of lawful justification.
Why It Matters in Research
This term is a marker for primary source depth. Researchers encountering IMPRISONAMENTUM in a text are working with materials that draw on Fleta or its contemporaries — thirteenth- and fourteenth-century English legal treatises operating in the Law Latin register. The term will not appear in modern statutes, case reporters, or most post-seventeenth-century legal literature under this spelling.
The dual-element structure embedded in the term is historically significant: it anticipates the analytical framework that would underpin the common law tort of false imprisonment and the writ of habeas corpus as remedies for unlawful detention. Researchers tracing the intellectual genealogy of either doctrine should note how early the common law distinguished the act of seizure from the act of continued holding — a distinction that remains operative in modern false imprisonment doctrine.
The Fleta quotation preserved in Burrill is a gateway into the primary source. Fleta, composed around 1290, is a substantial treatise modeled on Bracton and survives as one of the key documentary sources for understanding how medieval common lawyers conceptualized personal wrongs. Any research into the deep historical roots of liberty of the person, habeas corpus, or false imprisonment will benefit from engagement with that tradition, of which this term is a part.
Researchers should also be alert to spelling variants. Law Latin texts use imprisonamentum, but the root verb imprisonare and related forms appear across different manuscript traditions. Bibliographic searches in early legal databases or digitized manuscripts may require variant searches.
Historical Dictionary Support
Burrill's Law Dictionary is the sole historical dictionary source catalogued for this term, and its entry is compact but carefully chosen. Burrill does not define imprisonamentum at length; instead, he quotes directly from Fleta, lib. 1, c. 42, § 1, allowing the primary source to carry the definitional weight. This approach is characteristic of Burrill's treatment of Latin terms of art: he functions as a conduit to the original rather than as an independent interpreter.
The Fleta passage is genuinely instructive. The formulation — est enim imprisonamentum duplex delictum — is not merely descriptive but analytical, asserting a two-part structure for the wrong. This level of doctrinal precision in a thirteenth-century treatise reflects the maturing of common law thought about personal liberty in the period following Magna Carta.
No other major historical legal dictionaries in the standard reference shelf (Jacob, Tomlin's, Bouvier, Black's early editions) appear to carry a dedicated entry for this Latin form, making Burrill's entry the principal lexicographic reference point. Researchers relying on other shelf dictionaries who do not find the term should look under FALSE IMPRISONMENT or IMPRISONMENT for the anglicized doctrinal treatment.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: False Imprisonment; Habeas Corpus; Personal Liberty