Definition
Quod jussu (Latin: "which was done by order") is a Roman civil law action allowing a third party who contracted with a son or slave — at the express command of that son's or slave's father or master — to hold the authorizing father or master personally liable on the agreement. Because a son under paternal power (filius familias) or a slave (servus) lacked independent legal capacity to bind themselves to contractual obligations enforceable against the paterfamilias, Roman law developed a set of praetorian actions — the actiones adiecticiae qualitatis — to reach the principal behind the transaction. Quod jussu was the strictest of these: where the father or master had directly ordered (jussit) the transaction, the third party could bring this action for the full amount of the obligation, without any limitation to the peculium (the property the son or slave controlled). The maxim associated with it states: Quod jussu alterius solvitur pro eo est quasi ipsi solutum esset — "That which is paid by the order of another is the same as though it were paid to himself."
Common Confusion
Quod jussu is one of several related praetorian actions that modern readers and even historical dictionaries tend to collapse into a single concept. Researchers should distinguish it from:
- Actio de peculio: where the father or master had not authorized the transaction but the son or slave acted within the scope of their peculium; liability was capped at the value of the peculium.
- Actio institoria and actio exercitoria: where the father or master had appointed the son or slave as a business manager (institor) or ship's captain (exercitor); liability arose from that appointment rather than from a specific order.
- Actio tributoria: where the master knowingly allowed trading with the peculium and creditors shared proportionally in it.
Quod jussu is the only action in this family premised on a direct, specific command authorizing a particular transaction, which is why it imposed full (in solidum) liability without the peculium cap.
Why It Matters in Research
Researchers encountering quod jussu in pre-modern sources are almost certainly working in one of two contexts: Roman law scholarship and its civilian descendants, or historical common law commentary that borrowed Roman categories to analyze agency and vicarious liability. Neither context is especially well mapped in modern indices.
The term appears in treatises on agency, master-servant doctrine, and early commercial law — where commentators drew on the actiones adiecticiae qualitatis to explain why and when a principal ought to be bound by an agent's contracts. When researching the historical foundations of apparent authority or ratification in common law, quod jussu is the Roman antecedent that writers like Pothier and Blackstone's contemporaries invoked. Following the citation trail from quod jussu leads directly into civilian sources on mandate and negotiorum gestio that otherwise sit outside the common law researcher's usual orbit.
The maxim — quod jussu alterius solvitur pro eo est quasi ipsi solutum esset — appears independently in discussions of payment, novation, and delegation. It can surface in sources that make no direct reference to the actio itself, so researchers should index it separately from the action.
Corpus researchers should note that because quod jussu had no direct common law procedural equivalent, English and early American sources reference it primarily as doctrine rather than as a pleading form. Do not expect to find it in writs or forms books; look instead in treatise discussions of agency and commercial obligation.
Historical Dictionary Support
Black's Law Dictionary (both the first and second editions) and Burrill's Law Dictionary are in close agreement on quod jussu, which is unsurprising: all three lean on the same primary authority, Hallifax's Analysis of the Civil Law (b. 3, c. 2, no. 3), along with Justinian's Institutes (4.7.1) and the Digest (15.4). The definitions are functionally identical across all three sources, differing only in minor phrasing.
What the historical dictionaries do well is preserve the maxim and gesture toward the Digest citation, giving researchers a foothold in the primary Roman sources. What they do not do is situate quod jussu within the broader family of praetorian actions, explain the peculium cap that distinguishes it from actio de peculio, or trace its doctrinal influence on common law agency. A researcher relying solely on Black's or Burrill's will understand the bare action but miss its significance as a conceptual ancestor of vicarious liability doctrine. Halifax's Civil Law remains a useful secondary source for fuller treatment; the Digest title 15.4 (De his qui in aliena potestate sunt) is the primary Roman text.
Jurisdictional Note
Quod jussu has no direct procedural life in American or English common law courts. Its significance is doctrinal and historical. Civil law jurisdictions (Louisiana, Quebec, Scotland, and the mixed jurisdictions of South Africa and the Philippines) may encounter it in commentaries on agency and mandate, where the civilian tradition preserves Roman categories more explicitly.