Definition
In Roman civil procedure, a conjectio causae was a brief oral synopsis or summary of a case delivered by an advocate to the judge at the opening of trial. The term translates roughly as "a throwing together of the case" — a concise framing of the matter in controversy before substantive argument began. It functioned as an introductory statement, orienting the judge to the essential facts and legal questions at issue before the full hearing unfolded.
Why It Matters in Research
This term appears almost exclusively in discussions of Roman civil procedure and will surface primarily in treatises on civil law, canon law, and early modern Continental legal practice. Researchers working in pre-modern legal sources — particularly those touching on ecclesiastical courts, Scots law, Louisiana law, or other civil law jurisdictions — may encounter the term in procedural contexts where the formal stages of pleading and trial opening are described.
The practical significance: conjectio causae represents a discrete procedural stage, not merely a rhetorical device. Researchers should not conflate it with the full opening argument (which came later in the proceeding) or with written pleadings. In sources drawing on Roman procedure, the conjectio causae marks a specific moment — the advocate's first address to the judge — distinct from the narratio (formal statement of facts) or the later argumentatio.
Because this term has no direct analogue in common law procedure, historical dictionaries and encyclopedias working primarily within the English legal tradition tend to pass over it or treat it in minimal fashion. Researchers should look to civilian treatises and commentary on Roman procedure for fuller treatment. Calvin's Lexicon Iuridicum, cited by Black's, is among the reference works that addressed this terminology directly, suggesting the term was live enough in early modern civilian scholarship to require definition.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed.) provides the sole historical dictionary entry available in the Law Mind corpus for this term. It defines conjectio causae as a "statement of the case" and a "brief synopsis of the case given by the advocate to the judge in opening the trial," citing Calvin — a reference to the Lexicon Iuridicum Iuris Caesarei et Canonici of Johannes Calvinus (early 17th century), a standard reference for Romano-canonical procedure.
The definition is accurate but minimal. Black's does not elaborate on the term's procedural context, its relationship to other stages of Roman trial procedure, or its survival in later civil law practice. No other historical dictionary in the corpus addresses this term, which reflects the term's status as specialist vocabulary of the learned law rather than common legal usage in Anglo-American practice.
The citation to Calvin is notable: it signals that Black's drew this entry from civilian jurisprudence rather than English case law or statute, which is consistent with the term's origin and usage. Researchers should treat the Black's entry as a pointer toward civilian sources rather than as a self-sufficient account.
Jurisdictional Note
This term belongs to Roman and Romano-canonical procedure and has no recognized role in common law courts. It may be encountered in civil law jurisdictions (Louisiana, Quebec, and mixed legal systems) in historical sources, and in ecclesiastical court records drawing on canon law procedure.