Definition
In Roman and early medieval law, interdiction of fire and water (Latin: *aqua et igni interdictio*) was a form of banishment or civil exclusion by which a person was formally expelled from the community. The penalty worked by prohibiting others from providing the condemned person with fire or water — the two most basic necessities of civilized life. To be denied fire and water was to be denied shelter, warmth, and sustenance, effectively rendering the person an outlaw beyond the protection of law and society.
In practice, the interdiction operated as a sentence of exile. Those subject to it were stripped of citizenship, property rights, and the protection of Roman law. Anyone who harbored or assisted the interdicted person risked sharing in the penalty. The sentence was used in Rome against those convicted of serious public offenses, including treason and certain categories of homicide, and served as an alternative to direct capital punishment — the condemned could avoid death by leaving Roman territory permanently.
The concept carried forward, in attenuated form, into feudal and early common law traditions as a conceptual ancestor of outlawry, where a person declared an outlaw similarly lost legal standing and the protection of the king's peace.
Common Confusion
Interdiction of fire and water should not be confused with the civil law institution of *interdiction* as it developed in Scots law and Louisiana law, which refers to a judicial proceeding restricting the legal capacity of a person deemed incapable of managing their own affairs (comparable to guardianship or conservatorship in other systems). The two uses of the word "interdiction" share a root concept — removal or restriction of legal standing — but the Roman penalty of fire and water is a punitive public law measure, while the civil law interdiction of persons is a protective private law proceeding. Researchers encountering "interdiction" in historical sources must confirm which meaning is operative before drawing conclusions.
Why It Matters in Research
This term is almost exclusively a term of Roman law and legal history. Researchers are unlikely to encounter it in operative legal instruments from any modern jurisdiction, but it appears regularly in:
— Historical treatises on Roman criminal procedure and Roman public law, where it marks a critical distinction between capital and non-capital punishment.
— Comparative law scholarship tracing the development of outlawry, attainder, and civil death across Western legal systems.
— Foundations-of-law discussions in works on the history of citizenship, legal personhood, and the relationship between the individual and the state.
The principal research trap is the terminological overlap with civil law interdiction. Louisiana legal materials in particular use "interdiction" extensively in the protective/guardianship sense, and a keyword search across a mixed corpus will surface both meanings without distinguishing them. Researchers working in Scots law sources will encounter similar ambiguity, as Erskine's *Institutes* — cited in Bouvier — uses interdiction in the Scots civil sense, and Bouvier's own entry conflates discussion of the Roman penalty with Scots interdiction doctrine.
The deeper historical significance is structural: interdiction of fire and water is one of the earliest formal mechanisms by which a legal system reduced a person from full legal standing to a condition approximating civil death. It is therefore an important conceptual node for research into outlawry, attainder, civil death, and the history of legal personhood.
Historical Dictionary Support
Bouvier's Law Dictionary addresses this term, though the surviving fragment of the entry shifts quickly from the Roman penalty into a discussion of Scots interdiction — the restraint of a prodigal or otherwise legally limited person under bond, governed by a quorum of interdictors. Bouvier cites Erskine's *Principles of the Law of Scotland* (I. vii. 30–32) for the proposition that the restraint ceases when deaths among the quorum reduce their number below the required threshold.
This structural elision in Bouvier is itself instructive: by the time American legal dictionaries were being compiled in the nineteenth century, the Roman sense of the term was primarily of antiquarian and comparative interest, while the Scots civil sense had live practical application. Bouvier treats the two under one heading without sharply distinguishing them, which reflects nineteenth-century legal scholarship's habit of tracing institutions back to Roman origins without always marking cleanly where Roman law ends and modern doctrine begins.
What historical dictionaries largely omit: any sustained treatment of the procedural mechanics of the Roman penalty — how it was imposed, by what tribunal, under what circumstances it could be revoked — or its relationship to the parallel development of outlawry in Germanic and common law traditions.
Jurisdictional Note
The Roman penalty has no operative modern jurisdiction. The civil law institution of interdiction descending from related concepts remains active in Louisiana and in Scots law, but under rules entirely distinct from the ancient penalty. Research in Louisiana interdiction law should proceed from the Louisiana Civil Code directly, not from Roman law sources, except for historical framing.