Definition
Latin. In the civil law: peril, danger, hazard, or risk. Periculum operates in two related but distinct senses within legal contexts.
1. General sense: The risk or hazard of loss attaching to property or an obligation — most commonly invoked in the law of sale to determine which party bears the loss when goods are damaged or destroyed after contract but before delivery.
2. Technical sense: An accident or unforeseen event (casus) as distinguished from dolus (fraud or intentional wrong) and culpa (fault or negligence). In this narrower sense, periculum describes an occurrence that relieves a party from liability for non-performance of an obligation because the loss arose from neither bad faith nor carelessness.
The foundational maxim is periculum rei venditae, nondum traditae, est emptoris — the risk of a thing sold, but not yet delivered, is the buyer's. This rule, drawn from Roman law and transmitted through the civil law tradition, placed the risk of accidental loss on the purchaser from the moment of contract, regardless of whether delivery had occurred.
Common Language
Modern common usage (Wiktionary): An accident or casus, as distinguished from dolus and culpa, and hence relieving one from the duty of performing an obligation.
Historical common usage (Webster's 1913): Danger; risk. In a narrower judicial sense: accident or casus, as distinguished from dolus and culpa, and hence relieving one from the duty of performing an obligation.
The common-language definitions here happen to capture the legal meaning with unusual precision — both Webster's and Wiktionary reflect the technical civil law usage rather than the everyday sense of "danger." Researchers should still note that in ordinary historical Latin, periculum simply means peril or danger; the specialized legal narrowing to casus-as-distinct-from-fault is a Roman law construction, not a feature of general Latin usage.
Common Confusion
Periculum is sometimes loosely equated with any form of contractual risk or with the modern concept of force majeure. The distinction matters: periculum in the strict civil law sense is risk of accidental loss falling on a party without regard to fault — it does not require the supervening event to be extraordinary or unforeseeable in the modern force majeure sense. It also operates differently from excuses grounded in culpa or dolus, which involve assessments of the party's conduct. Conflating periculum with force majeure or with frustration of purpose doctrines in common law systems will produce anachronistic readings of historical sources.
Why It Matters in Research
Researchers encountering periculum in historical legal texts should be alert to which sense is in play — the broad "risk/hazard" usage or the narrower technical usage as casus divorced from fault. The two senses appear side by side in Roman and civil law sources and are not always clearly distinguished by the author.
The maxim periculum est emptoris is the most commonly cited instance and appears across civilian commentary, early American treatises, and treatises on sales law. Kent's Commentaries (2 Kent, Comm. 498–499) engages this maxim directly and provides a useful entry point for tracing how American jurists in the early republic received and modified the civil law rule. The common law tradition diverged on this point: later American and English sales law moved toward rules that more closely tied risk of loss to transfer of title or possession, a departure worth flagging when reading pre-20th-century sources.
In research involving Louisiana, Quebec, Scotland, or other mixed or civil law jurisdictions, periculum retains functional relevance longer and appears in local doctrine and judicial writing well into the modern period. In purely common law jurisdictions, the term is almost exclusively a historical or comparative law marker by the 19th century.
The Burrill entry's reference to the Digest (18.6) and the Code (4.48) gives researchers direct Roman law coordinates. Fleta, lib. 2, c. 58 is an additional medievalEnglish source that absorbed civil law concepts, and its citation by Burrill signals that periculum had some reception in English legal writing beyond pure civilian commentary.
Historical Dictionary Support
Black's (1st and 2nd editions) and Burrill's are in close agreement: all three define periculum as peril, danger, hazard, or risk in the civil law, and all cite or allude to the periculum est emptoris maxim. Burrill's provides the most specific source references, pointing to Digest 18.6, Code 4.48, and Fleta — details absent from Black's entries. None of the historical dictionary entries fully develops the technical distinction between periculum as casus and the separate concepts of dolus and culpa, which is the element that Webster's 1913 captures most clearly. Researchers relying solely on Black's for this term will miss the fault-taxonomy dimension that gives periculum its analytical precision in classical and post-classical civil law.
Jurisdictional Note
In civil law jurisdictions and mixed systems (Louisiana, Quebec), periculum and the periculum est emptoris rule had direct doctrinal force and appear in statutory and judicial sources. In common law jurisdictions, the term appears primarily in treatises and comparative discussions rather than in operative legal rules. Modern sales law in the United States (U.C.C. Article 2) has substantially displaced the civilian risk-of-loss framework, making periculum a largely historical term in American research contexts outside Louisiana.