Definition
A commodatum is a contract originating in civil law by which one party (the commodans, or lender) delivers a specific thing to another party (the commodatarius, or borrower) for temporary use, free of charge, with the obligation to return the identical thing after use or after the agreed period has elapsed. The transaction is gratuitous: no payment, rent, or compensation passes. Because the thing itself must be returned — not its equivalent — only non-fungible goods are proper subjects of commodatum.
Commodatum is a species of bailment. It corresponds most closely to what common law calls a loan for use, but it carries the more precise Roman-law framework governing the duties and liabilities of each party.
Common Confusion
Commodatum is frequently confused with mutuum and with locatio conductio rei (hire of a thing):
- Commodatum vs. mutuum: In a mutuum, fungible goods (grain, money) are delivered and the borrower need only return an equivalent quantity of the same kind — ownership transfers. In a commodatum, the specific object must be returned intact — ownership never passes.
- Commodatum vs. locatio conductio: The functional distinction is a single variable: payment. If the use is compensated, the contract is hire (locatio conductio), not commodatum. Both Burrill and Black's 2nd Ed. make this the defining line.
Researchers encountering "loan for use" in common law sources should verify whether the author is translating commodatum or using the phrase more loosely to describe any gratuitous bailment.
Core Elements
The classical formulation, consistent across the historical dictionaries, requires:
1. Delivery of a specific thing — the object must be identifiable and capable of being returned in specie.
2. Temporary use by the borrower — use is the purpose; the borrower does not acquire ownership.
3. Gratuitousness — no pay or reward, either accepted or promised (nulla mercede accepta vel constituta, per Burrill citing Dig. 13.6).
4. Obligation of return — the identical thing, not a substitute, must be restored at the end of the defined period or use.
Why It Matters in Research
Commodatum is a term of art with a stable Roman-law pedigree, but its appearance in common law sources requires care. Common law absorbed the concept through equity and through treatise writers — Story's Bailments being the most important conduit — but it never fully naturalized the Latin vocabulary. A source may describe the substance of commodatum while using only English phrasing ("gratuitous loan," "loan for use"), or conversely may use the Latin term while intending only a rough analogy.
When researching historical bailment cases, the commodatum/mutuum distinction is frequently dispositive: courts turned on whether title passed (mutuum) or remained with the lender (commodatum), because the answer determined who bore the risk of loss and what action lay. Researchers tracing this in older English and American cases should look for fact patterns involving specific chattels lent without payment, which is the commodatum pattern even when the word itself does not appear.
The commodatarius's standard of care is another productive research thread. Civil law imposed a higher-than-ordinary duty of care on the borrower because the loan was purely for the borrower's benefit — a principle that influenced Story and filtered into American equity decisions on gratuitous bailments. Sources in the Law Mind corpus that address bailee liability without compensation often track this rationale without citing Roman law directly.
Scottish, Louisiana, Quebec, and South African legal materials will use commodatum as active law rather than historical background, so jurisdictional context matters when reading secondary sources that treat the concept as merely academic.
Historical Dictionary Support
The historical sources align closely on substance. Bouvier offers the most economical definition: "a contract by which one of the parties binds himself to return to the other certain personal chattels which the latter delivers to him to be used by him without reward." Burrill adds the Digest citation (Dig. 13.6.1.1) and Bracton (fol. 99b), grounding the concept in its primary sources. Black's 2nd Ed. integrates the party nomenclature (commodans, commodatarius) and explicitly contrasts commodatum with locatio conductio on the gratuitousness axis, citing Story's Bailments.
Rapalje & Lawrence cross-references the commodatarius entry to "Bailee, § 2," which reflects the practical approach of those dictionaries: they translate civilian categories into common law functional equivalents rather than treating them as independent doctrine.
None of the historical dictionaries address the commodatarius's standard of care directly within their commodatum entries, though Burrill's fuller entry approaches it. Researchers seeking the liability rules must follow the cross-references to bailment and to Story.
Jurisdictional Note
In mixed civil-common law jurisdictions — Louisiana, Quebec, Scotland, South Africa — commodatum is operative positive law, not merely a historical category. In purely common law jurisdictions, the concept survives functionally as gratuitous bailment or loan for use, but the Latin terminology is largely confined to academic writing, equity opinions of the eighteenth and nineteenth centuries, and comparative law contexts.
Encyclopedia Cross-Reference
Law Mind Encyclopedia — Bailment
Law Mind Encyclopedia — Gratuitous Contracts
Law Mind Encyclopedia — Roman Law Foundations of Common Law Property