Definition
In civil law, a compromissarius is an arbitrator — specifically, a person appointed by mutual agreement of disputing parties to resolve a matter outside of formal court proceedings. The term derives from compromissum, the submission agreement by which parties bound themselves to accept an arbitrator's decision. The compromissarius was understood to function as a private judge empowered by the consent of the parties rather than by state authority.
Why It Matters in Research
This is a term of Roman civil law that appears in historical legal writing, particularly in texts drawing on the Digest and in early modern common law treatises discussing arbitration. Researchers encountering it in historical sources should recognize it as a technical synonym for arbitrator, not a distinct office or procedure. The important navigational point is that the underlying concept — submission to a mutually chosen decision-maker — maps onto the modern arbitration framework, but the term itself does not survive into contemporary legal usage. If you encounter compromissarius in a primary source, trace the text toward compromissum (the submission agreement) and arbiter ex compromisso (the alternative Latin designation for the same role), both of which illuminate the procedural context. The Rapalje & Lawrence citation to Jenk. Cent. 128 is a reference to Jenkin's Centuries, a collection of cases from the Exchequer, and suggests the concept was recognized in common law arbitration discussions as well. Researchers working in early arbitration history, civil procedure, or comparative law will find the cluster of compromissum, compromissarius, and arbiter ex compromisso appearing together in source texts.
Historical Dictionary Support
The four historical sources agree entirely on the core meaning: a compromissarius is an arbitrator in the civil law tradition. There is no divergence worth flagging.
Burrill provides the most substantive entry. He traces the term to compromissum, cross-references the Digest (Dig. 4.8.33 and 4.9.41), and supplies the alternative designation arbiter ex compromisso — a detail the other dictionaries omit. This is useful because it confirms that historical texts may use either form to describe the same role, and researchers should not treat them as distinct positions.
Rapalje & Lawrence contribute the maxim "Compromissarii sunt judices" (arbitrators are judges), drawn from Jenkin's Centuries. This formulation is instructive: it signals that within the civil law framework, the compromissarius exercised a genuinely adjudicative function, not merely a mediating one. The parties' prior agreement to be bound by the decision was what conferred this quasi-judicial character.
Black's (both editions) are brief to the point of being lookup entries only. They confirm the meaning but add nothing to the civil law context. Researchers needing substance should work from Burrill and Rapalje & Lawrence on this term.
What the historical dictionaries collectively omit: any discussion of how the role of the compromissarius related to the formal courts — specifically, whether a Roman court would enforce the compromissum or the resulting award, and under what conditions. That procedural layer requires direct engagement with the Digest materials Burrill cites rather than reliance on the dictionary entries alone.