Definition
In Roman civil law, noxia refers to an offense committed or damage caused by a person or thing under another's legal control — most commonly a slave or, in some usages, an animal. The term designates not the act itself in the abstract, but the specific wrong as it gives rise to liability on the part of the owner or master. When a slave committed a delict (a civil wrong), the slave's act was the noxia, and the owner faced a choice: pay compensation to the injured party or surrender the slave to that party in satisfaction of the claim. This surrender procedure was called noxal surrender (noxae deditio), and the action brought to enforce the owner's liability was a noxal action (actio noxalis).
Noxia should be understood as a term of art anchored entirely in the Roman law of delict and its structure of vicarious or quasi-vicarious liability. It has no living counterpart in modern common law doctrine.
Common Confusion
NOXIA / NOXA / NOXAE: These three forms appear interchangeably in translated sources and cause persistent confusion. Noxa is frequently used as a synonym for noxia, referring to the harm or wrong itself. Noxae is the genitive form, appearing in compound terms: noxae deditio (surrender on account of the wrong), actio noxalis (noxal action). Black's 1st and 2nd editions define noxia only; Burrill broadens the subject to include animals as well as slaves, reflecting a fuller reading of the Digest. Researchers should not treat these forms as distinct legal concepts — they are grammatical variants within the same doctrinal cluster.
Core Elements
The concept of noxia operated within a defined legal structure:
1. The wrongdoer: A slave (servus) or, under some texts, an animal (as Burrill notes from Digest 9.1.1.1). Free persons acting in paternal power (filii familias) were also subject to analogous noxal rules in early Roman law, though this application receded over time.
2. The act: A delict — theft, damage to property, injury — not a contractual breach. Noxia attached to wrongful acts, not to obligations voluntarily assumed.
3. The liable party: The owner or master at the time the action was brought, not necessarily at the time of the offense. Roman law followed the principle noxa caput sequitur — the liability follows the offender. If the slave was sold after committing the wrong, liability passed to the new owner.
4. The owner's election: Upon a noxal action being brought, the owner could either pay the assessed damages or surrender the slave bodily to the plaintiff (noxae deditio), thereby extinguishing further liability.
Why It Matters in Research
Noxia is a historical term with no active use in modern legal systems, but it is significant for researchers working in several areas.
Roman law foundations: Noxia is foundational vocabulary for reading the Institutes of Justinian (Book 4, Title 8) and the Digest (Title 9.1), the two primary sources cited across all three dictionary entries. Any research into the Roman law of delict, the development of vicarious liability, or the legal status of slaves in Roman private law will encounter this term repeatedly.
Comparative law and legal history: Scholars tracing the genealogy of modern tort doctrines — particularly employer liability, respondeat superior, and owner liability for animals — frequently engage with noxal liability as an ancestor concept. The structural logic of noxia (an owner held to answer for a subordinate's wrong, with a defined exit through surrender) is a recurring reference point in comparative legal history.
Source divergence on animals: Burrill's entry is meaningfully broader than either edition of Black's, explicitly including animals as subjects of noxia by reference to Digest 9.1.1.1. Black's both editions confine the definition to slaves. Researchers reading Burrill's entry will encounter the fuller Roman doctrinal picture, while Black's entries present only the core case. Neither is wrong, but they are not equivalent.
Translation variance: Because noxia, noxa, and related forms appear in Latin primary sources, English translations of Roman law texts vary in how they render these terms. Some translators use "offense," others "harm," "wrong," or "delict." The term should always be traced back to the Latin when precision matters.
Historical Dictionary Support
All three source dictionaries agree on the core definition: noxia is a wrong committed by a slave giving rise to noxal liability under Roman civil law. The Institutes citation (Inst. 4, 8, 1) is shared across all three, confirming the primary textual anchor.
The meaningful divergence is Burrill's inclusion of animals alongside slaves, supported by an additional citation to the Digest (Dig. 9. 1. 1. 1). This reflects the pauperies action under Roman law, by which an owner could be held liable — or could surrender the animal — for damage caused by a four-footed animal acting contrary to its nature. Black's both editions omit this dimension entirely. For a researcher interested only in the slave-law context, Black's is sufficient. For a researcher engaged with the broader Roman noxal system, Burrill's entry is the more complete starting point.
None of the three dictionaries address the noxa caput sequitur principle or the procedural mechanics of noxae deditio in any detail. Researchers needing that material must go directly to the primary Roman law sources or to secondary treatments in Roman law scholarship.
Jurisdictional Note
Noxia is a Roman civil law term with no direct application in common law jurisdictions. It surfaces in Louisiana civil law scholarship and comparative law literature, where Roman law concepts retain scholarly relevance, but it does not appear as operative doctrine in any modern American, English, or Commonwealth court.