Definition
A Latin term from Roman civil law meaning a giving, or the act of giving. Datio appears in legal sources in two principal senses:
1. Transfer by gift or payment. The basic act of conveying something to another. Most commonly encountered in the compound form datio in solutum — a giving in payment — which describes the satisfaction of a debt or obligation by transferring something other than what was originally owed. This is the civil-law ancestor of the common-law doctrine of accord and satisfaction. The modern form of this concept is dation (or dation en paiement in Louisiana and civilian jurisdictions).
2. Appointment or assignment. In Roman procedural law, datio also described the formal act of appointing an official. Datio judicis was the appointment of a judex — a private citizen designated to hear and determine a specific cause under the magistrate's authority. Datio tutoris was the appointment of a tutor or guardian, typically by a magistrate or public authority, to oversee the person or property of one legally incapable of self-management.
Common Confusion
Datio in solutum is not identical to accord and satisfaction in all respects, though historical dictionaries treat them as equivalents. Accord and satisfaction in common law requires mutual agreement plus performance; datio in solutum in the civil law tradition emphasizes the creditor's acceptance of a substitute performance and carries distinct rules about when title passes and when the obligation is extinguished. Researchers conflating the two may misread civilian authorities on the moment of discharge.
Datio should also be distinguished from donatio (gift). Datio encompasses transfers made in satisfaction of an obligation; donatio is a transfer made gratuitously, without an antecedent duty. The words look and sound alike in Latin texts, and historical sources do not always flag the distinction.
Recognized Forms
/SUBTYPES
Datio in solutum — Giving in payment; transfer of property other than what was originally owed, accepted by the creditor in full satisfaction of the debt. The foundational civilian concept underlying modern dation.
Datio judicis — Appointment of a judex in Roman civil procedure; the magistrate's act of designating a private person to serve as judge for a particular dispute.
Datio tutoris — Appointment of a tutor or guardian by public authority, distinct from testamentary or statutory guardianship arising by operation of law.
Why It Matters in Research
Datio appears primarily in Roman law sources and in civilian jurisdictions that inherited Roman legal vocabulary. Researchers working in Louisiana law, Quebec law, or comparative private law will encounter dation en paiement as a living doctrine — the civilian counterpart to accord and satisfaction — and need to understand its datio roots to trace doctrinal arguments accurately.
In historical common-law sources, datio surfaces mainly as a borrowed term in equity and contract discussions, where writers reaching for Roman authority deploy it without always distinguishing its subtypes. A citation to datio in a nineteenth-century English or American treatise is almost always a reference to datio in solutum and should not be read as invoking the appointment meanings.
The procedural meanings — datio judicis and datio tutoris — are relevant almost exclusively in Roman law scholarship and in historical analysis of ecclesiastical or civil-law guardianship systems. They rarely carry forward into modern legal argument, but they appear in foundational works on Roman procedure (Hallifax's Analysis of the Civil Law, Gaius's Institutes) that Law Mind researchers may consult for historical background.
Watch the transition from datio to dation in nineteenth-century sources. American writers, particularly in Louisiana, begin using dation as the Anglicized equivalent. Finding datio in an older source and dation in a later one does not signal a doctrinal shift — it is ordinarily just a terminological modernization.
Historical Dictionary Support
Black's (1st and 2nd editions) and Burrill agree on the core definition: datio is a giving or act of giving, with datio in solutum as its primary legal application. All three sources identify the modern equivalent as dation and note the connection to accord and satisfaction.
Burrill adds the procedural dimensions — datio judicis and datio tutoris — that Black's omits, and cites Hallifax's Analysis of the Civil Law for the judicial appointment meaning. This is a genuine substantive addition, not mere elaboration. Researchers relying solely on Black's will miss the appointment sense entirely.
None of the historical dictionaries distinguish meaningfully between datio in solutum as a Roman doctrine and its reception in modern civilian systems, nor do they address the doctrinal differences between datio in solutum and common-law accord and satisfaction. That gap is significant for comparative research.
Jurisdictional Note
Louisiana is the primary American jurisdiction where datio in solutum survives as operative law, codified as dation en paiement. The doctrine is also active in Quebec and in Latin American civil-law systems. In common-law jurisdictions, datio functions as historical vocabulary only.