Definition
In Roman civil law, the action available to a hirer (conductor) against the person who let a thing for hire (locator). Where a contract of hire — locatio conductio — was formed, it gave rise to reciprocal obligations and, correspondingly, to two distinct actions. The conducti actio (sometimes called ex conducto actio) was the hirer's remedy: it allowed the conductor to sue the locator for failure to deliver the thing hired, interference with the hirer's use and enjoyment, breach of warranties, or other defaults by the party who let the property or services. The mirror-image action, the locati actio, ran in favor of the locator against the conductor — most commonly for unpaid rent or hire.
The underlying contract, locatio conductio, encompassed what modern law would treat as three distinct relationships: the hire of a thing (locatio rei), the hire of services or labor (locatio operarum), and the hire of a specific piece of work (locatio operis faciendi). The conducti actio was available across all three forms, adapted to the facts of each arrangement.
Common Confusion
Conducti actio and locati actio are the two sides of the same contractual relationship and are frequently mentioned together. The confusion to avoid: conducti actio belongs to the hirer (conductor), not to the letter. The Latin root conductor in Roman law means "one who hires" — not, as the English word suggests, one who manages or leads. A researcher encountering either term in a historical source should immediately identify which party is suing which before applying the label.
Why It Matters in Research
This term will appear almost exclusively in discussions of Roman law, civil law jurisdictions, and comparative legal history. It has no direct modern common-law counterpart and is unlikely to surface in American or English case reporters except in academic commentary or treatises addressing the Roman origins of contract and lease law.
For corpus researchers, the primary trap is the English false cognate: "conductor" in modern English means something entirely different from conductor in Roman law. Any search using the term conductor in a historical legal corpus may retrieve results about transport law, railroad liability, or orchestra management rather than locatio conductio. Targeted searches using the full Latin phrase — conducti actio or ex conducto actio — will filter noise effectively.
The alternate form ex conducto actio appears in Burrill and in the Digest sources he cites (Dig. 19.2.15), and researchers should treat both forms as equivalent. Entries in historical dictionaries that use only one form without cross-referencing the other may cause a researcher to believe they are separate actions; they are not.
The term has no meaningful jurisdictional variation in the common-law world because it never entered common-law doctrine. In civil law scholarship and in the work of institutional writers who engaged with Roman sources — Heineccius, Pothier, and their successors — the term appears as a doctrinal building block for understanding hire, lease, and service contracts. Researchers tracing the ancestry of modern lease law or employment contract doctrine in Louisiana, Quebec, or mixed civil-law systems will find this term as a node in that lineage.
Historical Dictionary Support
The four source dictionaries are in close agreement. All define the conducti actio as the hirer's action against the letter, and all anchor the definition to the same Roman source: Institutes 3.25 (pr. 2), which addresses the obligations and remedies arising from locatio conductio. The definitions are functional rather than analytical — they identify the parties and the direction of the action without elaborating on what specific defaults trigger it.
Burrill's entry is the most useful of the four. It is the only one to supply the alternate form ex conducto actio, cite the Digest reference (Dig. 19.2.15), and point readers to Heineccius's Elementa Juris Civilis (lib. 3, tit. 25, § 929) for substantive treatment. Burrill also cross-references the entry Conductio, which provides the broader contractual framework. Black's (both editions) and Rapalje & Lawrence offer compressed versions of the same core definition, adequate for identification but insufficient for research into the doctrine's substance. None of the historical dictionaries address the three-way subdivision of locatio conductio or explain how the conducti actio operated differently across hire of a thing, hire of labor, and hire of work — a gap that researchers will need to fill from institutional sources or treatises on Roman law.