Definition
Triatio is a Latin term from old English law meaning trial. The word derives from the Latin *triare*, to try, and appears in medieval and early modern legal texts as the formal Latin designation for the proceeding by which a matter is judicially determined.
Two specific applications appear in historical sources:
1. Triatio in the general sense: the trial of a cause before a jury or tribunal.
2. Triatio bilinguis: a "bilingual trial," referring specifically to trial by a jury de medietate linguæ — a mixed jury composed half of native subjects and half of aliens, used when one of the parties was a foreigner. This procedure ensured that a party unfamiliar with the language and customs of the realm had jurors drawn from their own community.
Why It Matters in Research
Researchers encountering *triatio* in Latin legal manuscripts, Year Books, or early common law reports should recognize it as a technical term with a narrow procedural meaning, not merely a generic reference to litigation or dispute. The maxim *triatio ibi semper debet fieri, ubi juratores meliorem possunt habere notitiam* — trial ought always to be had where jurors can have the best information — reflects the medieval rationale for venue, grounding jurisdiction in the jury's local knowledge rather than in abstract rules of territorial authority. This principle surfaces repeatedly in early venue and vicinage disputes and is worth tracing when researching the historical foundations of the right to trial in the vicinage.
The compound form *triatio bilinguis* is particularly useful for researchers examining the legal status of alien merchants, diplomatic subjects, and foreign traders in medieval and early modern England. The jury de medietate linguæ was a recognized procedural protection with a documented history in English commercial law and admiralty practice. Molloy's *De Jure Maritimo et Navali*, cited in Burrill, is a legitimate seventeenth-century treatise and a reliable primary source for this usage in maritime contexts. Researchers working on the history of aliens' rights, jury composition, or admiralty procedure should treat *triatio bilinguis* as a gateway term to that literature.
Because the term appears almost exclusively in Latin legal sources and has no modern procedural descendant in living law, it will not appear in contemporary digests or statutory indexes. Research must proceed through Latin legal glossaries, the Year Books, Coke's reports and *Institutes*, and specialized treatises on English legal history.
Historical Dictionary Support
Burrill's Law Dictionary is the only source in the Law Mind shelf that treats *triatio* directly, and its entry is concise but well-grounded. Burrill supplies the derivation, the general definition, the vicinage maxim with attribution to Coke's Reports (7 Co. 1, Bulwer's Case), and the *bilinguis* variant with attribution to Molloy. Spelman's *Glossarium Archaeologicum* is cited as further support for the general meaning, which is consistent with Spelman's role as a standard reference for medieval Latin legal terminology.
No other historical dictionaries in the Law Mind corpus — not Jacob, not Tomlin, not Black's early editions — carry a dedicated entry for *triatio*. This reflects the term's confinement to Latin legal writing and its displacement by the English word "trial" in practical usage by the time legal dictionaries became common. Researchers should not expect to find the term treated outside of Latin glossaries and specialized common law scholarship.
The vicinage maxim attributed to Bulwer's Case is genuine and was well-known in early modern common law practice; Coke invoked it as authority for the principle that juries should be drawn from the locality where the facts arose, a principle with lasting influence on venue doctrine.