Definition
Latin: "things alleged and things proved." A maxim of civil procedure and evidence law expressing the foundational principle that what a party proves at trial must correspond to what that party alleged in the pleadings. A litigant cannot plead one case and establish a different one through evidence. The allegations frame the case; the proof must answer to those allegations. Courts hear and decide a cause secundum allegata et probata — according to what has been alleged and proved.
The maxim operates in two directions. First, evidence offered at trial must be confined to the issues raised in the pleadings. Second, a judgment must be supported by both a pleaded claim and proof of that claim. Neither allegation without proof nor proof without allegation is sufficient.
Common Confusion
ALLEGATA ET PROBATA is sometimes loosely equated with the concept of the burden of proof, but the two are distinct. Burden of proof governs how much proof is required and who must supply it. Allegata et probata governs the relationship between what is pleaded and what is proved — it is a rule of correspondence, not a rule of sufficiency. A party may fully satisfy the burden of proof on a point never alleged, and still lose on allegata et probata grounds.
The maxim is also occasionally confused with the variance doctrine. Variance is the procedural consequence of a mismatch between allegation and proof; allegata et probata is the underlying principle that makes variance a problem. One is the rule, the other is the remedy for breaking it.
Why It Matters in Research
Researchers working in equity, admiralty, or early common law pleading records will encounter this maxim as a live doctrinal standard, not mere Latin decoration. In those contexts, courts regularly dismissed or limited claims on allegata et probata grounds — meaning the maxim functions as an operative holding, not a background principle.
The phrase appears most frequently in older American and English equity decisions, where pleading was formal and factual specificity in the bill of complaint was mandatory. In modern federal practice, the maxim's force has been substantially absorbed by doctrines of variance, judicial notice, and the notice-pleading rules under the Federal Rules of Civil Procedure. Researchers should not assume that modern cases will use this Latin phrase even when applying the same underlying principle.
A key trap in historical sources: the allegata et probata requirement was stricter in equity than at common law. Common law courts allowed some latitude through amendment; equity courts were less forgiving, and a bill that failed to allege a material fact could not be rescued by proof alone. Sources that blur this distinction may mislead on the actual historical standard.
The maxim also appears in international arbitration and civil law jurisdictions, where it retains more explicit doctrinal currency than in modern American common law courts. Researchers working in comparative or transnational contexts should not treat this as a purely historical term.
Historical Dictionary Support
Black's Law Dictionary (both editions) provides the same terse definition: "things alleged and proved," with the ancillary maxim that an allegation contrary to the deed is not admissible. These entries give the literal translation and the basic principle but offer no procedural texture.
Burrill's Law Dictionary is the more substantive source here. Burrill frames the term as a general rule of evidence, states the operative prohibition — a party may not "state one case, and make out a different one by proof" — and supplies judicial authority. The reference to Baldwin, J. in 10 Peters' Reports 177 and Story, J. in 2 Sumner's Reports 206 reflects genuine early nineteenth-century federal equity practice, where the maxim was treated as an active procedural constraint rather than a learned reference. Burrill also preserves the Greenleaf evidence treatise citation (1 Greenl. Evid. § 51), locating allegata et probata within the mainstream evidence literature of the period.
The historical dictionaries converge on the core rule but diverge on emphasis. Black's treats it as a definitional entry; Burrill treats it as a working doctrine. Neither source adequately addresses the equity/common law distinction, and neither anticipates the absorption of the maxim into modern procedural rules. Researchers relying only on Black's will miss the doctrinal weight the phrase carried in its active period.