Reus in exceptione fit actor
“The defendant, in raising a defense, becomes the plaintiff.”
Roman law maxim
What does “Reus in exceptione fit actor” mean?
Reus in exceptione fit actor translates as “The defendant, in raising a defense, becomes the plaintiff.”
A defendant who raises a defense must prove it, just as a plaintiff must prove a claim. It is a basic rule on the burden of proof.
“Reus in exceptione fit actor” word by word
| Latin | English | Grammar |
|---|---|---|
| Reus | defendant | nominative singular masculine of reus, “party to a lawsuit, defendant”; the subject of the sentence |
| in | in, by means of | preposition governing the ablative; here it marks the means or occasion |
| exceptione | a defense, a plea | ablative singular of exceptio, “exception, special plea”, in Roman procedure a defense that adds new facts to the case |
| fit | becomes | third person singular present indicative of fio, “I become”, which also serves as the passive of facio |
| actor | plaintiff | nominative singular masculine of actor, “one who brings a claim”; it completes the verb fit, so it stands in the nominative |
How to pronounce “Reus in exceptione fit actor”
The two systems differ in exceptione: classical has the hard k sound of c and a clear t, while Church Latin has ch and a ts sound (“tsee”). Stress falls on the first syllable of reus, on the -O- of exceptione, and on the first syllable of actor.
The story behind it
Word for word the maxim says “the defendant in a defense becomes plaintiff”. It is a rule of Roman law on the burden of proof, and no individual author is known for it. It belongs to the body of legal maxims passed down through Roman and medieval jurists.
The idea comes from Roman civil procedure. The plaintiff (actor) had to prove his claim. A defendant who simply denied it had nothing to prove, but one who raised an exceptio, a defense resting on new facts such as payment or a release, took on the plaintiff’s role for that point and had to prove those facts himself.
Lawyers still quote it. Modern civil-law and common-law systems follow the same principle: whoever asserts a fact bears the burden of proving it, including a defendant who pleads an affirmative defense.
How to use “Reus in exceptione fit actor”
A fitting epigraph for a law student’s notes on evidence and procedure, a heading in a study guide on the burden of proof, or a line in a legal essay or moot-court argument. It suits a specialist setting better than a general motto.
- Latin
- Reus in exceptione fit actor
- English
- The defendant, in raising a defense, becomes the plaintiff.
- Source
- Roman law maxim
- Era
- Legal Latin
- Theme
- Law
Common mistakes
- Reus does not mean “guilty”. It means the party who has to answer in court, in civil cases the defendant.
- In exceptione means “in raising a defense”, not “in an exception” in the loose everyday sense. Exceptio is a technical term of Roman procedure.
- Fit comes from fio, “to become”, not from the verb “to be”. Actor is the complement of fit and so takes the nominative, not the accusative.
- The maxim does not say a defendant who simply denies the claim takes on any burden. It applies only once he raises a defense of his own.
Questions about “Reus in exceptione fit actor”
What does “Reus in exceptione fit actor” mean literally?
“The defendant in a defense becomes plaintiff.” In plain terms, a defendant who raises a defense takes on the claimant’s role and must prove it.
Who said “Reus in exceptione fit actor”?
No single author is known. It is a maxim of Roman law, handed down in the legal tradition rather than tied to one named jurist.
How do you pronounce “Reus in exceptione fit actor”?
In Classical Latin: RAY-oos in eks-kep-tee-OH-neh feet AHK-tor. In Church Latin the c of exceptione becomes ch: eks-chep-tsee-OH-neh.
What does “actor” mean in this maxim?
It means the plaintiff, the party who brings a claim and must prove it. It does not mean “actor” in the theatrical sense.
More to explore
Translation and grammar checked by Latin Quoter · last reviewed November 2026
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