Definition
Vadiatio is a medieval Latin legal term meaning "wager" or "pledge," used in early English law to describe the formal act of staking a pledge in connection with judicial proceedings. The term appears primarily in two procedural contexts: vadiatio duelli (wager of battle), the trial by combat in which parties pledged to settle a dispute by personal combat or through champions, and vadiatio legis (wager of law), the procedural device by which a defendant swore an oath of denial supported by a fixed number of compurgators. Both forms were modes of proof or trial in the medieval common law, predating the modern jury system as mechanisms for resolving contested facts or claims.
Common Confusion
Vadiatio is sometimes loosely equated with "vadium," a related but distinct term referring to a pledge of property as security — roughly analogous to a gage or mortgage. The confusion arises because both derive from the same root concept of pledging or staking something of value. Vadiatio, however, specifically denotes the procedural act of waging in a judicial context, while vadium more typically describes a proprietary or security arrangement. Researchers encountering either term in medieval records should not treat them as interchangeable.
Recognized Forms
/SUBTYPES
Vadiatio duelli: The wager of battle. A form of trial in which the parties (or their champions) pledged to resolve a dispute through personal combat. The outcome was treated as divine judgment on the merits. Formally abolished in England in 1819.
Vadiatio legis: The wager of law. A form of trial in which a defendant swore denial of a claim and produced a set number of oath-helpers (compurgators) who swore to the credibility of the denial. Available in certain forms of action, notably debt, and gradually displaced by jury trial before being formally abolished.
Why It Matters in Research
Vadiatio is a term researchers will encounter primarily in medieval English legal sources — plea rolls, treatises such as Glanvill, Bracton, and Fleta, and early statutory material — rather than in modern case law or secondary commentary. Its significance lies almost entirely in understanding pre-modern procedure. A researcher who encounters the term in a primary source without recognizing it as procedural vocabulary may misread the nature of the proceedings being described.
The two subtypes, vadiatio duelli and vadiatio legis, each have their own extensive procedural histories and appear under a range of related terms (gage, gager, wager, pledge) depending on the language of the source — Latin, Law French, or early English. Burrill's cross-reference to Blackstone's Commentaries (Book III) is a useful anchor: Blackstone treats both wager of battle and wager of law as curiosities already archaic in his own time, providing narrative explanation that helps a researcher understand what the procedural terms actually meant in operation.
The term appears in Fleta (lib. 2, c. 53), one of the thirteenth-century treatises closely related to Bracton, making it important for researchers working in that stratum of early English legal literature. Because vadiatio appears almost exclusively in Latin sources of this period, researchers working with later English-language materials will rarely encounter the Latin form — they are far more likely to see "wager of battle" or "wager of law" in the same sense.
Historical Dictionary Support
Burrill's entry is brief but accurate in its core identification: vadiatio as wager, with the two recognized procedural forms. The Burrill entry is notable for a textual anomaly — it appears to contain interleaved text from the entry for "vagabond," suggesting a printing or compilation error in the dictionary itself. Researchers consulting Burrill directly should be aware that the passage reading "worthless person. Vagabonds are described... as such as wake on the night and sleep on the day" belongs to a separate entry and is not part of the definition of vadiatio. Only the final two sentences of the Burrill passage — referencing wager of battle, wager of law, and the Blackstone and Fleta citations — properly belong to the vadiatio entry.
No other sources in the present corpus provide independent entries for vadiatio. Its historical meaning, however, is well-attested across the standard medieval legal treatises, and Blackstone's treatment in the Commentaries remains the most accessible secondary account for English-language researchers.
Jurisdictional Note
Vadiatio is a term of English law exclusively. The wager of battle was abolished by statute in England in 1819 (59 Geo. III, c. 46); wager of law had fallen into disuse well before formal abolition. Neither procedure took root in American law, and the term has no operative legal meaning in any modern jurisdiction.