Iura novit curia

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.

[3] 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.

[4] 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.

The codes of procedure may also provide that the court may call upon the parties or experts to prove or determine any applicable foreign law.

In the English, Irish and Scottish systems, on the other hand, the court has a less active, or even a passive, role: the procedure is generally based on the assumption that the court has no independent knowledge of the law, that it is dependent upon the submissions advanced by counsel for the parties, and that its function essentially is to adjudicate on the exclusive basis of their submissions.

[8]Jacobs explains, however, that this distinction is exaggerated on closer examination: Civil law courts, iura novit curia notwithstanding, may not exceed the limits of the case as defined by the claims of the parties and may not generally raise a new point involving new issues of fact.