Definition
Latin. A thing done; a deed or act. In legal usage, *actum* (plural: *acta*) refers to a completed legal act or formal proceeding — something accomplished, as opposed to something merely intended or in progress. The term appears most commonly in two contexts:
1. As the initial or concluding word of historical instruments and records, where "actum" introduces the dating clause to indicate when and where a transaction was formally executed or completed.
2. More broadly in civil law tradition, as a synonym for a legal act or proceeding — any formal step taken in the course of legal business, whether a private transaction or a judicial proceeding.
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Common Confusion
ACTUM vs. ACTUS: These are closely related Latin forms and are frequently treated as interchangeable in historical legal sources, but they carry distinct emphases. *Actum* is properly the neuter past participle of *agere* (to do, to drive, to transact), functioning as a noun meaning "a thing done" or "a deed." *Actus* is the masculine noun form derived from the same root, used in Roman law more broadly to denote an act or action in progress or as a category — including the physical act of driving animals or vehicles across land (a recognized servitude type). Researchers encountering either form in civil law or early English records should not assume the terms are functionally equivalent without context. Burrill treats *actus* as the primary entry and *actum* as its variant; Black's reverses the emphasis.
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Why It Matters in Research
Researchers in the Law Mind corpus will encounter *actum* almost exclusively in two contexts: (1) diplomatic and paleographic records from medieval and early modern English legal instruments, where it signals the *eschatocol* — the concluding protocol block containing the date and place of execution; and (2) civil law treatises and Digest citations, where it appears as part of broader discussions of legal acts and obligations.
The dating clause use is the more practically significant for documentary researchers. In Latin instruments, "Actum apud..." or "Actum anno..." introduces the place and date of execution, distinguishing where the act was *done* from where a document was later witnessed or enrolled. Confusing the actum clause with other parts of the instrument — particularly the *datum* clause (when the document was issued or delivered) — can produce errors in dating. Medieval diplomatic scholars distinguish *actum* (the underlying transaction) from *datum* (the moment of documentary delivery), though in many records these collapsed into a single clause.
For civil law research, the term feeds into larger doctrines around legal acts (*acta*) as a category — see *negotium*, *instrumentum*, and related terms. The plural *acta* in Roman and canon law denotes the official record of judicial proceedings, a distinct usage from the singular transactional sense.
Historical English common law sources will rarely use *actum* as a live term of art; its appearance in English legal texts is almost always a marker of civil law influence, ecclesiastical court practice, or antiquarian documentary discussion.
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Historical Dictionary Support
Black's (both editions) gives a spare, identical definition: "a deed; something done." This is accurate but strips the term of contextual specificity. It does not distinguish the diplomatic clause usage from the civil law doctrinal usage, and gives no guidance on the *actum/actus* relationship.
Burrill is more useful. He correctly identifies *actum* as the initial word of the concluding clause in instruments — a navigational detail Black's omits — and provides the Digest citation (*Dig.* 46.8.5) for the civil law usage, grounding the term in primary Roman law sources. His treatment of *actus* as the fuller entry, with *actum* as a variant or related form, reflects the standard approach of 19th-century civil law lexicography.
Neither dictionary addresses the diplomatic distinction between *actum* and *datum* clauses, which is the most practically significant point for researchers working with original instruments. For that, researchers should consult diplomatic handbooks rather than legal dictionaries.
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Encyclopedia Cross-Reference
Law Mind Encyclopedia — Deeds and Instruments
Law Mind Encyclopedia — Roman Law and Civil Law Foundations
Law Mind Encyclopedia — Canon Law and Ecclesiastical Courts (for *acta* as judicial records)
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