Definition
Vicarius is a Latin legal term meaning a deputy, substitute, or person acting in the place of another. In its primary legal sense, it describes anyone who steps into another's position to exercise authority on their behalf — a delegate, agent, or stand-in empowered by a superior to act where the superior cannot or does not act directly.
The term carries two historically distinct meanings:
1. DEPUTY OR SUBSTITUTE (Roman and Civil Law): One who acts in the place of another (qui vice fungitur alterius). This is the foundational sense — vicarius denotes a functional stand-in whose authority derives entirely from the person above them in a chain of delegation. The maxim vicarius non habet vicarium (a deputy cannot have a deputy) flows directly from this meaning: because the vicarius holds only delegated power, they cannot re-delegate it further without express authorization. This principle is the Latin root of the modern delegata potestas doctrine.
2. SLAVE OF A SLAVE (Roman Civil Law): In Roman law, vicarius had a secondary, narrower meaning — the slave of a slave, or a sub-slave assigned to serve another slave rather than the master directly. This usage appears in the Digest and has no meaningful survival in modern legal doctrine.
---
Common Language
Modern common usage (Wiktionary): "Vicarious" in English means experienced in the imagination through the actions of another person; performed or suffered by one person as a substitute for another.
Historical common usage (Webster's 1913): "Vicarious" — acting or suffering for another; as, a vicarious sacrifice; also, performed or suffered in place of another.
The gap between common and legal meaning here runs in an interesting direction. The English derivative "vicarious" has drifted toward the experiential (vicarious thrills, vicarious liability as something felt or borne at one remove), while the Latin legal original vicarius points to something structural and hierarchical — a formal relationship of substituted authority. A researcher encountering vicarius in a historical legal text should resist the softer modern sense: this term signals a precise delegation relationship, not mere secondhand participation.
---
Common Confusion
Vicarius is the noun form; vicarious (and vicarious liability) are the derived English terms. Researchers sometimes treat these as interchangeable, but they are not. Vicarius in a historical source names the person — the delegate himself. Vicarious liability in modern tort law describes the legal responsibility of a principal for an agent's acts. The connecting thread is delegation and substituted authority, but the terms operate at different levels: vicarius identifies a role; vicarious liability identifies a consequence of that role relationship.
Vicarius should also be distinguished from procurator and mandatarius, which are related but distinct civil law categories of agents or delegates.
---
Why It Matters in Research
The practical importance of vicarius in Law Mind corpus research is almost entirely in two directions: the maxim vicarius non habet vicarium, and the civil law of agency and delegation.
MAXIM RESEARCH: The phrase vicarius non habet vicarium is one of the more frequently invoked Latin maxims in older Anglo-American legal writing and in ecclesiastical and civil law contexts. Researchers tracing the delegata potestas doctrine — the principle that a delegated power cannot be re-delegated — will encounter vicarius as the nominal anchor of that maxim. Broom's Legal Maxims is the standard bridge source cited in Burrill and elsewhere; cross-referencing that text against the encyclopedia entry on delegata potestas will help establish how far common law courts adopted this civil law principle.
CIVIL LAW SOURCES: In Roman and civil law texts, vicarius appears in the Digest (Digest 33.8.6.3 for the slave-of-a-slave usage) and broadly throughout titles dealing with agency, manumission, and property in slaves. Researchers working in the civil law tradition or in mixed jurisdictions (Louisiana, Quebec, Scotland, South Africa) should expect vicarius in its delegation sense to appear in doctrinal writing on mandate and agency, and in the slave sense to appear in texts on Roman property law and manumission.
ECCLESIASTICAL LAW: Vicarius has deep roots in canon law and ecclesiastical governance — vicar, vicar-general, and vicar apostolic all derive from this term and carry formal canonical meanings. Researchers working in ecclesiastical law or in the intersection of church and civil authority will find vicarius used with technical precision in that tradition, distinct from its purely civilian meaning.
HISTORICAL TRAP: Because vicarius is pure Latin and appears without translation in many older texts, researchers may encounter it without gloss and need to infer from context which sense is intended. The deputy/delegate sense is by far the more common in English legal writing; the slave-of-a-slave sense is limited almost entirely to civilian and Roman law scholarship.
---
Historical Dictionary Support
Burrill's Law Dictionary is the primary source here, and it captures the essential structure cleanly: vicarius as deputy or substitute, the maxim vicarius non habet vicarium with a citation to Broom's Maxims, and the Roman civil law sense from the Digest. Burrill's entry is brief but reliable.
What historical dictionaries tend not to provide is much on the ecclesiastical dimension, where vicarius has its richest institutional history. The vicar in English law — particularly the vicar as incumbent of a parish receiving small tithes, in contrast to a rector — derives from this same root and was a figure of some legal consequence in tithe litigation and ecclesiastical court practice, but that usage typically appears under vicar or vicar-general rather than under the Latin form.
The slave-of-a-slave meaning, while accurate to Roman law, is correctly treated by Burrill as a secondary and historically specific usage. No modern legal system preserves it as operative doctrine.
---
Jurisdictional Note
Vicarius as a term of art has greatest relevance in civil law jurisdictions (Louisiana, Quebec, and jurisdictions drawing on Roman law foundations), in canon law contexts, and in historical English legal writing. Common law jurisdictions generally replaced the Latin form with the English derivative terms — deputy, agent, delegate — but the maxim vicarius non habet vicarium (and its principle) was cited in English and American courts well into the nineteenth century.
---
Encyclopedia Cross-Reference
See Law Mind Encyclopedia — Delegata Potestas (for the maxim and re-delegation doctrine)
See Law Mind Encyclopedia — Agency and Delegation (for the modern doctrinal context)
See Law Mind Encyclopedia — Mandate (Civil Law) (for the Roman and civil law tradition)
---