Jura novit curia

Iura novit curia is a Latin legal maxim expressing the principle that "the court knows the law", i.e., that the parties to a legal dispute do not need to plead or prove the law that applies to their case.

The maxim is applied principally in civil law systems and is part of the investigative ("inquisitorial") aspect of that legal tradition, as distinguished from the more pronouncedly adversarial approach of common law legal systems. The maxim is first found in the writings of the medieval glossators about ancient Roman law.

Iura novit curia means that the court alone is responsible for determining which law applies to a particular case, and how. The court applies the law ex officio, that is, without being limited to the legal arguments advanced by the parties (although the court is normally limited to granting the relief sought by the parties). The same principle is also expressed in the related maxim da mihi factum, dabo tibi ius ("give me the facts and I shall give you the law"), sometimes also given as narra mihi factum, narro tibi ius: it is incumbent on the parties to furnish the facts of a case and the responsibility of the judge to establish the applicable law. The maxim also means the parties cannot limit the court's legal cognition (that is, the authority to determine the applicable law).

In its most wide-reaching form, the principle of iura novit curia allows the court to base its decision on a legal theory that has not been the subject of argument by the parties. However, in view of the parties' right to be heard (audiatur et altera pars) and the adversarial principle, both also recognized in civil law systems, this freedom is not unlimited. Many jurisdictions require the court to allow the parties to address any points of law first raised by the court itself.

Because a wide application of iura novit curia may conflict with the parties' authority (in private law) to decide what is to be the subject of litigation, courts in most jurisdictions normally stay within the bounds established by the pleadings and arguments of the parties. In criminal law, the court's freedom to apply the law is generally constrained at least to some extent by the legal characterization of the alleged facts in the indictment.

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