Definition
Facio ut des (Latin: "I do that you may give") is a type of innominate contract originating in Roman civil law. It describes an arrangement in which one party performs an act or renders a service in exchange for the other party's promise to pay a price — either a sum agreed upon in advance or an amount to be determined by operation of law. The classic example is an employment relationship in which a worker performs labor for a master in exchange for agreed wages.
The term belongs to a classical Roman taxonomy of contracts organized by the nature of the exchange. The four innominate contract forms are: do ut des (I give that you may give), do ut facias (I give that you may do), facio ut facias (I do that you may do), and facio ut des (I do that you may give). Each formula captures the structure of the reciprocal obligation: the first word names what the promisor does; the final words name what the promisee must do in return.
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Common Confusion
Facio ut des is one of four innominate contract formulas and is frequently confused with facio ut facias ("I do that you may do"), which governs exchanges of services for services rather than services for payment. The critical distinction is the nature of the return obligation: facio ut des involves a monetary or fungible return, while facio ut facias involves a reciprocal act. Researchers encountering any of the four formulas in historical sources should identify the specific form rather than treating them interchangeably.
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Why It Matters in Research
This term appears almost exclusively in historical and comparative legal sources. Researchers are unlikely to encounter facio ut des in modern common law opinions or statutes; its natural habitat is treatises on Roman law, early English common law commentary, and nineteenth-century contract theory. Blackstone's Commentaries (2 Bl. Comm.) uses the innominate contract taxonomy to explain foundational contract principles that English law inherited or adapted from Roman sources, making facio ut des a useful conceptual anchor when reading Blackstone-era materials.
The practical research trap: the innominate contract taxonomy was used by historical writers to categorize agreements that lacked recognized names under Roman law. When a historical source invokes facio ut des, it is often making a structural point about the enforceability of informal or unnamed agreements — not merely describing a labor contract. Understanding the taxonomy helps researchers recognize when an author is engaging in doctrinal classification versus describing a specific type of transaction.
Modern common law does not use this terminology. The concepts it expressed have been absorbed into general contract doctrine — offer, acceptance, consideration, and quantum meruit (for cases where the price is unspecified). When researching the historical foundations of implied contract, quasi-contract, or quantum meruit claims, the innominate contract taxonomy — and facio ut des specifically — is a useful bridge between Roman civil law sources and early common law development.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) provides the only entry among the shelf sources and defines the term concisely and accurately: "I do that you may give. A species of contract in the civil law (being one of the innominate contracts) which occurs when a man agrees to perform anything for a price either specifically mentioned or left to the determination of the law to set a value on it." The Blackstone citation (2 Bl. Comm.) grounds the term in the standard English-language authority for Roman law's influence on common law development.
No modern edition of Black's Law Dictionary carries a substantive entry for this term, reflecting its displacement from active legal use. The 2nd Edition's inclusion signals that the term was still considered part of the working vocabulary of legally educated readers in the early twentieth century, particularly those trained in civil law traditions or classical legal education. Historical dictionaries do not meaningfully diverge on this term; it is a stable Latin formula with a fixed referent.
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Jurisdictional Note
Facio ut des is a civil law concept with no direct counterpart in modern common law jurisdictions. It retains relevance in jurisdictions with mixed legal systems (Louisiana, Quebec, South Africa, Scotland) where Roman law concepts remain part of the active doctrinal vocabulary, and in comparative law scholarship more broadly.
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