Definition
"Riens lour deust" (Law French: "not their debt") is an archaic plea in which a defendant denied owing the debt claimed by the plaintiff. It is an early form of what later became the plea of *nil debet* — the general denial of indebtedness in a common-law debt action. The plea put the plaintiff to proof that the debt existed and was owed.
Common Confusion
Researchers may conflate *riens lour deust* with the later Latin plea *nil debet* ("he owes nothing"). The two are substantively equivalent — *riens lour deust* is the earlier Law French expression of the same denial. The distinction matters only for dating and language of source: if a record uses *riens lour deust*, it is almost certainly pre-modern English; *nil debet* persisted much longer and into early American common-law pleading. Neither should be confused with *non est factum* (denial that a document was made), which is a denial of a different fact entirely.
Why It Matters in Research
This term will appear only in medieval and early English common-law sources. Researchers working in pre-modern pleading records, Year Books, or early English legal histories should treat it as a linguistic predecessor to *nil debet* rather than a distinct substantive doctrine. The term itself is not in active use in any modern jurisdiction and would not appear in post-medieval case law or statutes.
The primary research trap is encountering this phrase in a historical source and failing to recognize it as a pleading formula. Because it is Law French — the technical language of English courts from roughly the Norman Conquest through the seventeenth century — it may appear without translation or explanation in older texts, particularly in record rolls and early abridgments. The connection to *nil debet* is the essential bridge: understanding one unlocks the other.
Researchers using Reeves' *History of the English Law* (the source cited by both Black's and Burrill's) should note that Reeves treats the plea in the context of the early development of debt actions, situating *riens lour deust* within the period before pleading forms had fully crystallized into the standardized Latin formulas of later common law. That developmental context is important: the plea reflects a moment when the courts were still conducting significant business in French rather than Latin or English, and when pleading terminology had not yet been rigidly systematized.
Historical Dictionary Support
Black's Law Dictionary and Burrill's Law Dictionary agree closely. Both identify the term as Law French and both trace it to the same source: Reeves' *History of the English Law*, volume 2, page 332. Burrill is slightly more expansive, supplying the translation "not their debt" and explicitly labeling it "an old form of the plea of nil debet," which is the more useful framing for a researcher. Black's entry is minimal — essentially just a citation — and adds little beyond Burrill's account.
Neither dictionary provides procedural detail about how the plea operated, what actions it was available in, or what consequences followed from its use. Researchers seeking that context must go directly to Reeves or to secondary works on the history of English pleading.
No modern legal dictionary is likely to carry this term, and its absence from American sources is expected: the plea was already archaic well before American courts developed their own pleading traditions.