luris ignorantia nocet, facti ignorantia non nocet

(a) Error iuris nocet: the position in Roman law

Finally, however, there was one kind of mistake which normally the Roman lawyers do not seem to have regarded as excusable, and that was the error iuris.

'* Frier. (19831 100 ZSS 293.

® (19831 100 ZSS 289 sqq. (2911.

⁵⁸ Cf. in general e.g. Heinz Hübner, "Subjektivismus in der Entwicklung des Privatrechts", in: Festschrift fur Max Kaser (1976), pp. 715 sqq.

^ACf. Ulp. D. 18, 1, 9, 2.

^9d On this text cf. Schmidlin, Rechtsregelti, pp. 36 sqq.; Laurens C. Winkel, Error iuris nocet— Rechtsdwaliny als rechtsordeprobleem (1982), pp. 149 sqq.

Lab. /Paul. D.'22, 6, 9. 3.

Paul. D. 41, 4, 2, 15. On error iuris in Roman law generally (apart from the recent book by Winkel), cf. Voci, L'errore, pp. 211 sqq.; Paul van Warmeto, "Ignorantia iuris", (1954) 22 TR 1 sqq.; Zilletti, op. cic, note 19, pp. 254 sqq.; Theo Mayer-Maly, "Error iuris", in: lus Humanitatis, Festschrift fur Alfred Verdross (1980), pp. 147 sqq.; Henryk Kupiszewski, "Ignorantia iuris nocet", in: Sodalitas, Scritti in onore di Antonio Guarino, vol. Ill (1984), pp. 1357 sqq. ignorantia are obviously used interchangeably.⁴⁸ Furthermore, the rule appears to be of considerable antiquity, for Labeo already advocated a restriction:

"Sed iuris ignorantiam non prodesse Labeo ita accipiendum existimat, si iuris consult! copiam haberet vcl sua prudentia instructus sit, ut, cui facile sit scire, ei dctrimento sit iuris ignorantia...."^w

Originally it appears to have been taken for granted that a Roman citizen should know the law; after all, until the days of Cicero, schoolboys had to learn the text of the XII Tables by heart.¹⁰⁰ By that time, however, the ius civile, as contained in this venerable codifica­tion, had been overlaid with a number of individual enactments as well as by a whole body of law developed by the praetor.

"^s Cf. also Mayer-Maly. Festschrift Verdross, p. Io0.

⁰⁹ Lab./Paul. D. 22. 6. 9. 3; for details, see Winkel, op. rit.. note 95. pp. 113 sqq.

“ Cf. Alfred Pernicc. Labeo, vol. II. 1 (2nd ed.. 18951. p. 424.

ⁿ At the end of the fragment the comment, "quod raro accipiendum est". has been added (by Paul?; in post-classical times?), the intent of which is not entirely clear. Cf. Christian Friedrich Miihlenbruch, "Uber iuris et facti ignorantia and deren Einfluss auf Rechtsver­hältnisse", (1821) 2 Archivfiir die civilistisclie Praxis 382 sqq.; but sec Mayer-Maly, Festschrift Verdross, p. 151.

" "Late Republican sources paint a discouraging picture of indefiniteness and insecurity in the judicial system of Rome: the procedural forms of the Edict shifted constantly; rhetorical advocacy remained supreme in harsh adversary trials; broad social commitment to minimum standards of formal justice was still lacking; public ignorance of law was widespread...; and, at the margin of this pandemonium, a handful ofjurists struggled to establish a place for their tenuous legal science": Frier, Roman Jurists, p.

^ICß "In omni parte error in iure non eodem loco quo facti ignorantia haberi debebit, cum ius finitum et possit esse et debcat. facti interpretatio plerumque etiam prudentissimos fallat." Lauterbach, Collegium theoretico-practimm. Lib. XXII, Tit. VI, IV added that the interpretatio facti is a matter "ubi tarnen ad minimum septem circumstantiae considerandae veniunt, scilicet, Causa, Persona, Locus, Tempus, Qualitas, Quantitas ct Eventus".

¹⁰¹ Cf. Vincenzo Scarano Ussani, Vh/on e storia nella cultura giumdica fro Nerva e Adriano (1979), pp. 5 sqq.; Winkel, op. cit., note 95, pp. 81 sqq. with this kind of argument that a hard line on error iuris was usually taken with regard to specific, fairly recent acts of legislation¹"⁵—as, for instance, decrees of the Senate such as the SC Silanianum,^{[3116] [3117]} the SC Macedonianum^[3118] or the SC Velleianum.^{[3119] [3120]} The constitutio Antonini-ana led to a flurry of problem cases (and induced a policy of tightening- up),^11)y for many of those who had been granted Roman citizenship lacked a detailed knowledge of the Roman laws.^[3121] But it was only in post-classical times that the emperors, concerned about the enforcement of the law, laid down a general duty to know the law: "Leges sacratissimae, quae constringunt omnium vitas, intellegi ab omnibus debent",^{[3122] [3123]} or, to quote the interpretatio to Codex Theo-dosianus 1, 1, 2: "Leges nescire nulli liceat, aut quae sunt statuta contemnere.^1,112 Certain groups of persons, however, were exempted from these stringent requirements: women, soldiers, minores XXV annis and rustici^[3124] (i.e. people stricken by rural simplicity).^[3125]

The maxim of error iuris nocet is based on the idea that one should know the law: "[non] stultis solere succurri, sed errantibus."^[3126] At least in classical Roman law, however, this was not considered to be a hard- and-fast rule.

(b) Error vincibilis and invincibilis (ins commune)

In any event, the authors of the ius commune proceeded to restrict the relevance of ignorantia (or error) facti accordingly. By the time of the usus modernus, the opinion had gained ground that a mistake relating to factual circumstances could be taken into account only if it was invincibilis^[3129] (or probabilis),^[3130] that is, ifit could have been avoided by taking proper care. But what was to be regarded as proper care under these circumstances? By and large, it was held that gross negligence made the error inexcusable: "Error iustus est ille qui caret latissima et lata culpa."^[3131] The ignorance must not be based on negligentia crassa^[3132] or, as others put it, it must not be "supina et affectata".^[3133] Various attempts were made to refine these criteria. Thus, particularly, a distinction was drawn between ignorantia facti proprii and ignorantia facti alieni.^[3134] Of one's own personal sphere one could, as a rule, be expected to have a clear and detailed picture; exceptions were, however, made for very complicated affairs and propter memoriae imbecilitatem:^{[3135] [3136].. in iis quae antiqua sunt, aut valde intricata, facti proprii errorem tolerabilem esse ac excusare.1,125 Matters falling outside one's own sphere one could, of course, not be required to know equally well.}

The distinction between own and other matters, incidentally, dates back to Pomponius, who had, however, introduced it in the context of mistakes relating to law.^[3139] This is quite typical of the specific relevance and influence of the Digest title 22, 6 on the development of the law of contract. An error iuris as such occurs but rarely when a contract is concluded.^[3140] Predominantly, the parties err about factual circum­stances. But error iuris tended to be taken as the prototype of an error attributable to negligentia crassa and hence inexcusabilis. A generaliza­tion of this rationale provided the dogmatic basis for limiting the rule of ignorantia facti non nocet to cases of ignorantia invincibilis.^[3141]

(c) Error iuris (ius commune and modem law)

But what became of error iuris itself?^[3142] The glossators regarded a person who did not know the law as unworthy of legal protection.^[3143] The moral theologians were somewhat more lenient; a legal norm, they argued, can bind only those to whom it is known.^[3144] Nevertheless, the error iuris continued to be discriminated against; "error iuris regulariter non praesumitur, sed scientia" became a widely accepted rule of procedure, which lived on in France in the form of the famous adage "nu/ n'est cense ignorer la /of.^[3145] Some of the writers of the usus modernus questioned the distinction between ignorantia iuris and facti. Augustin Leyser abandoned it in favour of the more basic categories of error vincibilis and invincibilis.^[3146] Lauterbach advocated an exception from error iuris nocet "in juribus difficilioribus".^[3147] To 18th-century enlightened authoritarianism, on the other hand, "error iuris nocet" was bound to appeal.

10.