Definition
Latin: "while he was in prison." A now-abolished writ of entry in old English law that enabled a person to recover lands he had alienated while under duress of imprisonment. The writ proceeded on the principle that a conveyance made by a person unlawfully or coercively confined lacked the free consent necessary to constitute a valid alienation, and that the grantor was therefore entitled to have the estate restored to him. It belonged to the broader family of writs of entry — real actions designed to recover seisin of land — and targeted the specific circumstance of duress by imprisonment as the vitiating condition.
The writ is of purely historical significance. It was abolished in England by statute (3 & 4 William IV) along with the other real actions, and it has no operational counterpart in modern common law practice.
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Common Confusion
Dum fuit in prisona is sometimes encountered alongside the related writ dum fuit infra aetatem ("while he was under age"), which addressed alienations made during minority rather than during imprisonment. The two writs share structural logic — both void a prior alienation on account of incapacity or coercion at the time it was made — but they address distinct defects and should not be conflated. Researchers encountering either writ in historical sources should confirm which vitiating circumstance is at issue before drawing analogies to modern doctrine.
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Why It Matters in Research
This term appears almost exclusively in historical legal sources — English Year Books, early treatises, and reports of real actions — and has no modern procedural life. Researchers are most likely to encounter it when tracing the doctrinal ancestry of duress as a vitiating factor in property transfers, or when working through the history of real actions in pre-Judicature Act English law.
Several navigational points are worth flagging:
First, the writ belongs to the class of writs of entry, a category that confuses modern researchers because "entry" in this context means something technically specific: a form of real action for recovering possession grounded on a defect in the title of the current possessor, not merely the physical act of entering land. Understanding the writ requires understanding where it sat within that taxonomy.
Second, the abolition occurred as part of the broader sweep of real property procedural reform in the 1830s. When a historical source cites the writ without noting abolition, that source likely predates or simply omits the statutory change. Cross-reference against the date of the source before assuming the writ was operative at the time discussed.
Third, modern duress doctrine in contract and property law does not descend directly from this writ in any clean line. The writ addressed a narrow procedural remedy; contemporary duress doctrine in equity and contract developed through separate channels. Researchers should resist over-reading the writ as evidence of a continuous or codified duress doctrine in real property law.
Finally, the writ is a useful anchor for understanding how medieval and early modern English law conceptualized the relationship between personal liberty and the validity of legal acts. It presupposed that imprisonment could, by itself, render a conveyance voidable — an assumption with significant implications for how courts thought about consent, coercion, and the conditions for valid alienation.
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Historical Dictionary Support
The three source dictionaries are in close agreement on substance. All three identify the writ as a form of entry to restore lands alienated under duress of imprisonment, and all cite Coke's Institutes (2 Inst. 482) as the primary authority. Burrill adds a reference to Roscoe's Real Actions, which provides useful practical detail for researchers who want more than Coke's summary.
The definitions are uniformly brief, which reflects the writ's status even in the period of these dictionaries: a historical artifact rather than a living instrument. None of the sources elaborate on the procedural mechanics of how the writ operated — how it was pleaded, what the defendant could traverse, or how judgment was rendered — because by the time these dictionaries were compiled, those details had ceased to matter practically. Researchers needing that level of procedural detail should go directly to Coke or to Roscoe's Real Actions rather than relying on dictionary treatments.
Burrill's note that the writ was "abolished with the preceding writ" is a useful pointer: the preceding entry in Burrill is dum fuit infra aetatem, indicating these writs were treated as a pair and abolished together. This contextual grouping helps situate dum fuit in prisona within the broader reform of real actions.
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Jurisdictional Note
This writ was an instrument of English common law and was never transplanted into American practice in operative form. American jurisdictions that received English common law did not adopt the old real actions as a functioning system, and duress in property transfers has been addressed through equity and contract doctrine rather than through writ-based real actions. The term is therefore relevant to American legal research only in historical or comparative contexts.
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