Definition
Jerarium is a Latin term from Roman law referring to the treasury — that is, the public fiscal repository of the Roman state. The term is a variant or corrupted form of aerarium, the classical Latin designation for the Roman treasury, particularly the aerarium populi Romani, the central public treasury of the Roman Republic housed in the Temple of Saturn in Rome. In Roman legal and administrative usage, the jerarium (aerarium) denoted both the physical storehouse of public funds and, by extension, the institutional concept of the state's financial administration.
As a legal term, jerarium appears primarily as a Latinate reference in civil law scholarship and glossaries, where it functions as a descriptor of the public fisc rather than as an operative term in legal doctrine. It is closely associated with fiscus, the imperial treasury that gradually superseded the aerarium in practical significance during the Roman Empire.
Why It Matters in Research
This term is encountered almost exclusively in historical civil law texts, glossaries, and Latin legal dictionaries. Researchers should approach it with two cautions.
First, the spelling jerarium is itself a signal of textual transmission issues. The standard classical and legal Latin form is aerarium. The j-form is likely a product of manuscript transcription, early print-era Latinization conventions, or a compositor's error — a pattern common in early modern legal printing where initial vowels were sometimes rendered with a j or i. Any researcher encountering jerarium in a historical source should treat it as equivalent to aerarium and search both forms.
Second, Black's 2nd Edition Supplemental entry cites "Calvin" — almost certainly referring to Johannes Calvinus (Johann Kahl), whose Lexicon Juridicum (various editions, 17th century) was a major civil law reference work and a source for many Latin legal terms in early Anglo-American legal dictionaries. This attribution is useful for tracing the term's lineage: it is a civil law borrowing, not a common law term, and its presence in an American legal dictionary reflects the tradition of including Roman law vocabulary for courts and practitioners engaged with civil law materials.
Researchers using the Law Mind corpus should not expect jerarium to appear as an operative term in case law or statutes. Its utility is reference and context: understanding Roman fiscal institutions when interpreting civil law texts, historical property law discussions, or comparative law scholarship.
Historical Dictionary Support
Black's 2nd Edition Supplemental is the sole dictionary source providing this entry, and its treatment is minimal — a one-line gloss equating jerarium with the treasury and cross-referencing fiscus. The citation to Calvin (Calvinus, Lexicon Juridicum) places the term squarely in the civil law dictionary tradition rather than common law practice.
Historical legal dictionaries are largely silent on jerarium as a distinct term because the standard civil law vocabulary used aerarium. The j-form does not appear in classical Roman legal texts such as the Digest or the Institutes of Justinian, where aerarium is the operative form. What Black's captures is a variant that circulated in early modern legal Latin scholarship — useful to record for completeness, but not a term with independent doctrinal significance.
Researchers should note that Black's equates jerarium directly with fiscus via cross-reference, but this is an oversimplification. Aerarium and fiscus were historically distinct institutions: the aerarium was the republican-era public treasury under Senate control, while fiscus referred to the emperor's private treasury, which over time absorbed the public financial functions of the aerarium. By the later Empire, the distinction had largely collapsed, which may explain why some glossators treated them as interchangeable.
Jurisdictional Note
Jerarium has no operative role in any modern jurisdiction's law. It appears only in historical civil law scholarship and Latin legal glossaries. Jurisdictions with civil law foundations (Louisiana, Quebec, and mixed systems) may encounter aerarium in historical texts but not as actionable doctrine.