Definition
A Latin and Law Latin term meaning identity or sameness. Used in legal writing and pleading to assert that two things, persons, or subject matters under consideration are one and the same. The term appears in civil law and common law sources as a shorthand for the condition of being identical — not merely similar — and carries weight in contexts where the law requires strict correspondence between what was alleged, promised, conveyed, or adjudged and what is before the court.
Common Confusion
IDENTITAS should not be confused with mere similarity or resemblance. In legal contexts, the term asserts strict sameness, not approximate equivalence. This distinction matters in pleading, in the law of judgments (where identity of parties and subject matter governs res judicata), and in contract and conveyance disputes where the question is whether the thing described and the thing delivered are truly the same thing.
Why It Matters in Research
Researchers encountering IDENTITAS in historical legal texts — particularly in Latin maxims, civilian treatises, or early common law pleading manuals — should understand it as a technical assertion of strict identity, not a general claim of likeness. The term most commonly appears in the context of the maxim referenced by Burrill: ex multitudine signorum, which holds that identity is established or confirmed through the convergence of multiple identifying marks or characteristics. This is a doctrine of practical importance in disputes over the identity of persons, parcels of land, goods, and instruments.
The relevance of IDENTITAS extends to several research areas within the Law Mind corpus:
First, in pleading history, strict identity between the matter pleaded and the matter proved was a core technical requirement. A failure of identitas — a mismatch between allegation and proof — could be fatal to a party's case.
Second, in the law of res judicata and estoppel by judgment, courts required identity of parties, identity of subject matter, and identity of cause of action. Historical sources discussing these requirements sometimes used IDENTITAS as the shorthand term, particularly in treatises drawing on civilian tradition.
Third, in conveyancing and the law of property, questions of identity arose wherever a description in a deed, will, or grant needed to be matched to a physical thing in the world. The doctrine that multiple converging signs establish identity (ex multitudine signorum) was a practical tool for resolving ambiguities in descriptions.
Researchers should note that while IDENTITAS as a standalone headword is relatively rare in the historical dictionaries, the concept it names is pervasive in legal doctrine. When the term disappears from later dictionaries, the substance migrates into doctrinal treatments of identity of parties, identity of issues, and certainty of description.
Historical Dictionary Support
Burrill's Law Dictionary gives the entry its most concise form: IDENTITAS is L. Lat. for identity or sameness, with a cross-reference to the maxim ex multitudine signorum. This brevity reflects that the term is primarily a conceptual placeholder in the Latin vocabulary of law — its force comes from the broader doctrines it names rather than from any technical procedure attached to the word itself. Burrill's cross-reference is the key research pointer: the maxim on multiple signs of identity is where the doctrinal content lives.
Other historical dictionaries in the common law tradition do not typically carry IDENTITAS as a separate headword, having absorbed the concept into entries on identity, res judicata, and certainty in pleading and conveyancing. Researchers using Latin-heavy sources — civilian treatises, early equity materials, Roman law commentaries — will encounter the term more frequently than in standard common law digests.