Definition
Nominatio auctoris is a Latin term from Roman law meaning, literally, "naming of the author" or "naming of the grantor." It describes a procedural defense available to a defendant in a real property action who, when sued as the apparent possessor of land, discloses that he holds the property not on his own account but on behalf of, or by the title of, another person — the true possessor or grantor (the auctor). By making this nomination, the defendant steps aside and substitutes the named party as the proper respondent in the action. The defense operates as a form of third-party disclosure: the defendant effectively says, "I am not the right person to sue; the claim lies against the one from whom I hold."
Common Confusion
The term is sometimes loosely conflated with vouching to warranty or the common law device of vouching in a warrantor, but these are distinct mechanisms. Vouching to warranty (common law) was a procedure by which a defendant called in a third party to defend title and stand bound by the result. Nominatio auctoris, by contrast, was a Roman civil law plea that identified the actual possessor so that the plaintiff could pursue the correct party — it was more a disclosure of the real defendant's identity than an invocation of a warranty obligation. The two procedures share a family resemblance but operate under different doctrinal frameworks and should not be treated as equivalents in historical research.
Why It Matters in Research
This term appears almost exclusively in discussions of Roman and civil law procedure and enters English legal sources mainly through antiquarian and comparative channels rather than through the common law tradition proper. Researchers working in Black's Law Dictionary (2nd Ed.) will find the entry truncated — the source text as preserved breaks off mid-sentence — which is a known hazard with older dictionary editions that reproduced compendium sources imperfectly. Do not treat the partial entry as a complete definition.
For researchers tracing the influence of Roman procedure on civil law jurisdictions, nominatio auctoris is a useful index term. It connects to the broader Roman law of possession (possessio) and to the actio in rem, the real action by which ownership of property was litigated. In civil law systems derived from Roman sources — Louisiana, Quebec, and the mixed jurisdictions of South Africa and Scotland — procedural analogs to nominatio auctoris may surface under different names or within third-party practice rules. English common law did not adopt the doctrine directly, so its appearance in English-language legal dictionaries reflects the civilian learning of the compilers rather than operative common law practice.
When this term appears in historical treatises, it is typically in the company of discussions of the rei vindicatio (the Roman action to recover ownership of property), the distinction between possessor and owner, and the rules governing who could be properly named as defendant in property litigation. Researchers tracing these doctrines should treat nominatio auctoris as a navigational marker pointing toward civil law procedure rather than toward common law pleading.
The Wharton reference in Black's 2nd Edition situates this term within a broader collection of civil and Roman law entries that Wharton's Law Lexicon carried over from civilian sources. Wharton's treatment of Roman terms was often condensed and should be verified against primary civil law sources or dedicated Roman law treatises for substantive research.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) provides the only indexed source in the Law Mind corpus for this term, and the entry is incomplete as preserved — the definition breaks off during its description of the defendant's procedural position. The entry does establish the core meaning: a defendant sued as the apparent possessor of real property who invokes nominatio auctoris is alleging that another party is the true possessor and proper defendant. The civilian character of the term is confirmed by its explicit attribution to Roman law within the entry itself.
The truncation is significant. Historical legal dictionaries frequently suffered from typesetting errors, abridgment, and reproduction loss, and researchers should treat clipped entries as potentially incomplete rather than as authoritative statements of the full doctrine. Where the doctrine matters to a research question, the entry in Black's 2nd should be treated as a starting point only.
No divergence among historical sources can be assessed here because only one dictionary source indexed this term in the available corpus. That absence itself is informative: nominatio auctoris was not a staple of common law dictionaries and its coverage in English-language sources was thin and derivative of civilian learning.
Jurisdictional Note
This doctrine has no direct common law counterpart and is not operative in typical American or English common law procedure. Its practical relevance in modern research is primarily historical and comparative, with potential application in civil law jurisdictions or in analyzing the Roman law foundations of mixed legal systems.