Definition
Latin. "Peers of the realm." The collective body of English nobility entitled to sit in the House of Lords and, historically, to be judged by their fellow peers rather than by ordinary courts or juries. The phrase denotes the highest hereditary rank of the English constitutional order — dukes, marquesses, earls, viscounts, and barons — understood as a distinct legal estate with procedural and political privileges flowing from that status.
Why It Matters in Research
This is a term of historical constitutional significance that surfaces almost exclusively in older English and early American legal sources. Researchers will encounter it primarily in materials touching on the structure of the English Parliament, the composition of the House of Lords sitting as a court, and the privilege of peerage — particularly the now-abolished right of peers to be tried by fellow peers (peerage trial) rather than by a common jury.
The phrase appears in medieval and early modern sources as a technical designation distinguishing the high nobility from lesser lords, freeholders, and the commons. Understanding pares regni is prerequisite to following arguments about the constitutional role of the Lords, the origins of trial by jury (itself derived partly from the feudal concept of judgment by one's peers, or pares), and the structure of Magna Carta's guarantees. Chapter 39 of Magna Carta — "no free man shall be imprisoned... except by the lawful judgment of his peers" — is the linchpin connecting pares regni to the broader development of due process doctrine in both English and American law. American legal sources from the colonial and founding eras sometimes invoke pares regni when tracing the ancestry of jury trial rights.
Researchers working in the Law Mind corpus should note that this phrase appears not as a working legal term of American law but as a citation to English constitutional history. It tends to appear in encyclopedia articles, treatises on constitutional law, and commentaries on Magna Carta rather than in pleadings or practice guides.
Historical Dictionary Support
Both Black's and Burrill's treat the term identically and minimally: "Peers of the realm. Spelman." The shared citation to Sir Henry Spelman (whose Glossarium Archaeologicum, first published posthumously in 1664, remains a foundational source for medieval English legal terminology) reflects the term's deep antiquity and its status as a matter for legal antiquarians rather than practitioners. Neither dictionary elaborates on the constitutional role of the pares regni or their procedural privileges, leaving the researcher to pursue the substance elsewhere.
Burrill's entry is marginally more useful in context, appearing alongside the entry for PARFOURNY, which signals that both terms belong to the same layer of the historical record — Latin and Law French vocabulary from medieval English legal materials — rather than to living doctrine. The brevity of both entries is itself informative: by the time these dictionaries were compiled, pares regni had no practical application in American courts and was recorded as a historical referent rather than an operative term.
What the historical dictionaries do not address: the distinction within the medieval sources between pares regni (peers of the realm, i.e., the high nobility) and pares curiae (peers of the court, the vassal-peers who judged in a feudal lord's court) — a distinction that matters considerably when tracing the feudal origins of jury trial. Researchers who encounter pares in Magna Carta commentary without the qualifier regni should be alert to this distinction.
Jurisdictional Note
Pares regni is exclusively a term of English constitutional history with no operative meaning in American or Commonwealth jurisdictions as living law. The peerage trial privilege was abolished in England by the Criminal Justice Act 1948. American law absorbed the underlying concept of "judgment by one's peers" into the jury trial right but shed the aristocratic structure entirely.