Definition
"Regis" is a Latin genitive form meaning "of the king," appearing in English legal usage primarily as a component of compound Latin writs and phrases from the medieval common law. It is not itself a standalone legal term but functions as a modifier that identifies the royal character or authority attaching to a writ, office, or proceeding. Several distinct legal instruments bear this particle:
1. BREVE DE CLERICO ADMITTENDO / NE VEXES (or the writ commonly indexed under "Regis"): A writ addressed to a bishop directing him not to molest or compel the residence of a clerk (clergyman) who was lawfully employed in the king's service. Because royal service constituted an excuse for non-residence at a benefice, the writ operated as a discharge from ecclesiastical discipline on that ground.
2. AD JURA REGIS: A related writ or proceeding by which the Crown asserted or protected royal rights — referenced in Bouvier in connection with actions touching the king's title or prerogatives.
3. CLERICUS DE MERCATO REGIS (Clerk of the Market of the King's Gate): An ancient honorable office, incident to the royal court's practice of holding markets in the court's suburbs. The clerk witnessed verbal contracts, regulated commodity prices, inspected weights and measures, measured land, and held disciplinary power over tradespeople including authority to commit bakers and others to the pillory.
In each use, "regis" marks the instrument or office as deriving its authority from, or operating in service of, the Crown.
Common Language
Modern common usage (Wiktionary): A male given name; a surname.
Historical common usage: Not listed as a common English word in Webster's 1913; recognized as Latin for "of the king."
In ordinary modern English, "Regis" is encountered almost exclusively as a proper name. The legal and historical usage is strictly Latin and appears only in the context of medieval writs, royal offices, and Latin legal phrases. A researcher encountering "Regis" in a historical legal text should treat it as a Latin genitive and look for the full compound phrase rather than treating it as a standalone term.
Common Confusion
"Regis" is frequently encountered as a fragment in digest indexes and abridgments where it appears without the full writ name, leading researchers to mistake it for an entry heading rather than a modifier. The writ indexed under "Regis" in Black's first and second editions is the same instrument — a bishop-directed writ protecting a non-resident clerk in royal service — but the two editions truncate the entry differently, creating apparent inconsistency in secondary sources. "Regis" should also not be confused with "Rex" (the nominative form, used when the king is the active subject of a proceeding, as in Rex v. [defendant]) or "Regina" (the feminine form used during a queen's reign).
Why It Matters in Research
Researchers working in medieval English ecclesiastical law, Crown prerogative, or the history of royal courts will encounter "regis" as a recurring modifier across a wide range of instruments. The key navigational challenge is that historical dictionaries and digest abridgments often index these writs inconsistently — sometimes under the full Latin phrase, sometimes under "Regis" alone, sometimes under the English translation. Bouvier's cross-reference to "Ad Jura Regis" is a useful entry point for Crown rights litigation, but the entry is sparse and researchers should follow it to the underlying sources (Coke's Institutes in particular) for substantive treatment.
The Clericus de Mercato Regis entry in Bouvier illustrates a second research risk: offices bearing "regis" in their title may have exercised surprisingly broad jurisdiction — judicial, regulatory, and punitive — that is not obvious from the office name. A researcher tracing the history of market regulation, weights and measures, or informal commercial adjudication should flag every "regis" office as a potential jurisdiction source.
For corpus researchers: writs and phrases containing "regis" thin out sharply after the seventeenth century as Latin pleading was progressively abolished and royal writs were replaced by statutory forms. Encountering "regis" language in sources after 1733 (when English was mandated for legal proceedings) is a signal either of a historical quotation, a scholarly Latin usage, or an error in transcription.
Historical Dictionary Support
Black's (1st and 2nd editions) and Rapalje & Lawrence are in agreement on the core writ: a bishop-directed instrument discharging a non-resident clerk in royal service, citing 2 Inst. 264 (Coke's Second Institute) and Reg. Orig. 58 (the Registrum Omnium Brevium, the standard register of original writs). The second edition adds the citation to Reg. Orig. 58 and appends the minor/dower maxim from 4 Coke 71, which appears to be an editorial continuation of an adjacent entry rather than substantively related to the "Regis" writ — a formatting artifact worth noting when consulting the second edition.
Bouvier diverges by giving the Clericus de Mercato Regis its own substantive treatment, which the Black's editions omit entirely. This is the most historically rich account in the corpus: the clerk's evolution from contract witness to commodity regulator to quasi-judicial officer reflects the general pattern by which royal household offices accumulated jurisdiction over time. Bouvier's treatment also gestures toward the "Ad Jura Regis" proceeding without fully developing it, leaving a gap that historical dictionaries in this corpus do not fill.
None of the historical dictionaries in the Law Mind shelf treat "regis" as a standalone doctrinal term or trace its appearances systematically across Crown prerogative law. Researchers needing the full range of "regis" instruments should consult Fitzherbert's Natura Brevium and the Registrum Brevium directly.
Jurisdictional Note
These instruments are exclusively English in origin and have no direct counterpart in American law. Post-independence American courts occasionally cited the underlying principles (Crown service as excuse for non-performance of duties) by analogy, but the writs themselves were never adopted. Scottish and Irish legal practice had analogous Crown-service doctrines under different procedural names.