Definition
Special non est factum is a plea in an action on a specialty (a deed or instrument under seal) by which the defendant acknowledges having executed the document but argues that, due to specific circumstances, the instrument is not legally his deed and therefore not binding upon him. The defendant "specializes" the plea by setting out the particular reason the deed should not be enforced — such as that it was delivered conditionally as an escrow but turned over to the plaintiff before the condition was met, or that some other circumstance at execution or delivery vitiated the deed's legal effect.
The plea is a variant of the general plea of non est factum ("it is not his deed"), distinguished by its admission of execution coupled with a particular legal reason why the deed should nonetheless be treated as a nullity.
Common Confusion
SPECIAL NON EST FACTUM vs. NON EST FACTUM (GENERAL): The general plea of non est factum denies that the defendant executed the deed at all — identity, forgery, or radical alteration. Special non est factum admits execution but interposes a specific legal circumstance that negates enforceability. Conflating the two matters because the pleading standards and the factual issues they raise are distinct. A researcher who encounters "non est factum" in a historical record must read the surrounding pleadings to determine whether it is the general or special form before drawing conclusions about the nature of the dispute.
SPECIAL NON EST FACTUM vs. PLEA OF NON PERFORMANCE: Where a defendant argues simply that a condition precedent to the obligation was not met, this may sound like a non performance plea rather than special non est factum. The distinction is formal and technical: special non est factum attacks the deed's legal existence as the defendant's act, while non performance concedes the deed but contests the obligation to perform under it.
Why It Matters in Research
This term is narrow and procedural, arising exclusively in the common law pleading system for actions on specialties — primarily debt on bond or covenant. Researchers encountering it in pre-twentieth-century English or American case reports should understand several things:
First, the term belongs to the formal common law pleading world that largely disappeared with the Field Code reforms in American jurisdictions (mid-nineteenth century) and with English procedural reforms of the same era. After code pleading and then notice pleading replaced the old forms, the specific plea of special non est factum ceased to appear by name. Arguments that were once pleaded as special non est factum now appear as affirmative defenses asserting conditional delivery, fraud in the factum, or lack of operative delivery.
Second, because the plea admits execution, it opens a different set of issues than the general plea. Historical records involving this plea will contain evidence about delivery conditions, escrow arrangements, or circumstances at or after execution — not evidence about the identity of the signatory or the authenticity of the signature. This shapes what a researcher should expect to find in the surrounding record.
Third, the escrow scenario is the paradigm case in both Black's and Bouvier's: the defendant delivered the deed conditionally, the condition was never satisfied, yet the plaintiff obtained the instrument and brought suit. This escrow-based form of the plea connects directly to research on the law of conditional delivery, which remained active well past the decline of formal common law pleading.
Fourth, in the Law Mind corpus, this term is most likely to appear in treatises on common law pleading (Chitty, Gould, Stephen) and in reported cases from English courts and early American state courts through roughly the mid-nineteenth century. It will rarely if ever appear in twentieth-century sources except in historical or comparative treatments.
Historical Dictionary Support
Black's and Bouvier's agree on the essential structure: the defendant admits executing the deed but asserts circumstances making it "not his deed" in law. Black's provides the more concrete illustration — the escrow turned over prematurely or without satisfaction of the condition — while Bouvier's frames the plea more broadly to include any circumstance showing the instrument was not intended to be the defendant's deed or was not lawfully binding. The broader Bouvier's formulation is arguably more accurate as a general statement because the plea could encompass scenarios beyond defective delivery, including execution under duress or fraud in the factum, where the deed's character as the defendant's legal act is called into question for reasons other than delivery defects. Neither source provides substantial procedural detail about how the special matter was set out in the plea, a gap that treatise sources on common law pleading fill more completely.
Jurisdictional Note
This plea was a creature of English common law pleading and carried into American jurisdictions that followed that system. Its practical relevance is limited to actions tried under formal common law pleading rules, meaning English courts through the Judicature Acts and American courts through code pleading reforms — roughly pre-1850 in most U.S. states.