Definition
In Roman law, a term denoting imperial authentication. Allegata was the word emperors signed at the bottom of their rescripts and constitutions to signify official sanction. Under other instruments, the equivalent authenticating words were signata or testata. The term marks the document as having received direct imperial attention and approval.
More broadly in legal usage, allegata appears as the first half of the compound phrase allegata et probata — meaning "things alleged and proved" — referring to the allegations a party advances in a proceeding and the evidence produced in support of them. The rule that allegata and probata must correspond is a foundational principle of pleading and evidence: a party cannot allege one set of facts and then prove a materially different set. Recovery or judgment must rest on what was both pleaded and proven.
Common Confusion
Allegata is sometimes encountered in isolation and taken to refer only to allegations — the pleading side of the equation — without its necessary counterpart, probata. The two terms are conceptually inseparable in the allegata et probata doctrine. A court does not simply ask whether something was alleged or whether something was proved; it asks whether what was proved corresponds to what was alleged. Treating allegata as a standalone synonym for "allegations in general" misses the disciplining function the paired phrase performs in procedural law.
Why It Matters in Research
Researchers working in early American and English common law sources, equity practice, or Roman and civil law materials will encounter allegata most often in one of two distinct contexts: the narrow imperial-authentication sense and the broader allegata et probata doctrine. Conflating the two, or failing to recognize which sense a source is invoking, can distort interpretation of historical arguments about pleading sufficiency.
The allegata et probata rule has deep procedural consequences that persist in modern doctrine under different terminology. Contemporary requirements that pleadings and proof must align — that a plaintiff cannot recover on a theory not pleaded, or that a variance between pleading and proof may be fatal — are descended from this principle. When researching variance doctrine, amendment of pleadings, or the distinction between pleading and proof in both civil and criminal contexts, allegata et probata is the historical anchor concept.
In civil law jurisdictions and in American jurisdictions with strong civil law traditions (particularly Louisiana), this Latin framing appears with greater frequency and is treated more explicitly as an operative doctrine rather than mere background principle. Common law jurisdictions absorbed the substance of the rule without always preserving the Latin label; researchers tracing the rule's application in 19th-century American case law may find it cited directly in Latin in equity courts well after it had largely disappeared from common law pleading arguments.
Because allegata in its imperial-authentication sense is specific to Roman law materials, it is unlikely to appear in American primary sources except in historical or scholarly commentary. Researchers working in that sense of the term should consult Roman law and civil law references rather than American common law digests.
Historical Dictionary Support
Black's Law Dictionary (both editions) and Bouvier treat the imperial-authentication definition as primary, with Bouvier also providing the fuller allegata et probata entry and articulating the correspondence rule. Anderson's Dictionary of Law addresses the probatio side of the doctrine under separate headings, cross-referencing the burden of proof principle — that proof rests on the one who alleges, not the one who denies (ei incumbit probatio qui dicit, non qui negat) — rather than treating allegata as an independent headword. This division across the historical dictionaries reflects the compound nature of the term: the dictionaries collectively cover both senses but none provides a fully unified treatment.
Notably, the historical sources do not address how the allegata et probata correspondence requirement interacts with procedural mechanisms for amending pleadings to conform to proof — a development that became significant in American practice under reformed pleading codes and eventually the Federal Rules. Researchers should not assume the historical dictionary treatment reflects the full modern scope of variance and amendment doctrine.
Jurisdictional Note
Louisiana and other jurisdictions influenced by civil law tradition invoke the allegata et probata principle more explicitly and by name than common law jurisdictions. In federal practice and most common law states, the underlying rule survives in doctrines governing variance between pleading and proof and in requirements for conformance of pleadings to evidence, but the Latin formulation is largely absent from modern judicial opinions.