Definition
A judex delegatus is a delegated judge — a person who derives judicial authority not from a permanent office or general commission, but from a specific delegation of power by a superior judicial authority or sovereign. The term originates in Roman civil law and passed into canon law, English ecclesiastical practice, and military law, where it continued to designate a judge appointed for a defined purpose rather than sitting by virtue of a standing judicial position.
The concept rests on a fundamental distinction between ordinary jurisdiction (iurisdictio ordinaria), which attaches to an office, and delegated jurisdiction (iurisdictio delegata), which attaches to a person for a specific task. A judex delegatus holds only so much authority as the delegating power conveys — no more and no less.
Why It Matters in Research
Researchers encounter this term primarily in three distinct contexts, and conflating them produces error.
First, in Roman and civil law sources, judex delegatus appears as a technical term of procedure, governing the limits of a specially appointed judge's power. The Codex Justinianus rule that a delegated judge cannot re-delegate — expressed in the maxim quoted by Burrill — is a foundational civil law principle that resurfaces in ecclesiastical, admiralty, and equity proceedings. Researchers working in civilian-tradition jurisdictions or pre-modern English ecclesiastical courts must understand this rule to interpret jurisdictional disputes correctly.
Second, in English ecclesiastical law, the judex delegatus was a judge appointed by papal or archiepiscopal commission to hear specific causes. Because ecclesiastical courts operated partly on civilian principles, the term appears in English legal sources from the medieval period through the Reformation and beyond, particularly in probate, matrimonial, and tithe disputes. These appearances can confuse researchers expecting purely common law vocabulary.
Third, Black's connects the term to military law, where it describes judges delegated to courts-martial and similar tribunals. This usage is narrower and later, and researchers should not assume the civil law rules about re-delegation apply without modification in the military context.
The non-delegation rule — that a judex delegatus cannot sub-delegate authority unless the original commission expressly permits it, or the delegation comes from the sovereign — is the doctrinal heart of the term. It appears in disputes over jurisdictional validity across all three contexts and remains a point of research interest when examining whether a particular tribunal had authority to act.
Historical Dictionary Support
Burrill and Black's approach the term from different angles, and the gap between them is instructive.
Burrill treats judex delegatus as a civil law term and provides the operative Latin maxim from the Codex (3.1.5): a delegated judge holds the judicial office personally and cannot further assign it, except where the delegation originates with the emperor. This maxim defines the practical limits of delegated judicial authority and is the core doctrinal content researchers need. Burrill's entry is more precise for civilian and ecclesiastical sources.
Black's entry is fragmentary and somewhat puzzling as reproduced — the text appears garbled in transmission — but the substance points toward English military law usage, noting that in England the judex delegatus is generally a member of the relevant tribunal appointed for a specific cause or proceeding. This suggests Black's was working from a later, more anglicized usage that had traveled some distance from the Roman civil law original.
Neither dictionary adequately addresses the term's role in English ecclesiastical courts, which is arguably its most frequent appearance in pre-modern English legal records. Researchers relying solely on these entries will be underequipped for ecclesiastical record work.
Jurisdictional Note
The term carries the most doctrinal weight in civil law jurisdictions, canon law, and English ecclesiastical law. In common law jurisdictions, it appears chiefly as a historical label or in the military law context. Researchers working with Scottish law, admiralty records, or pre-Reformation ecclesiastical courts will encounter it more frequently than those working in post-1800 common law materials.