Definition
Latin: "inauspicious days" or "forbidden days." In Roman law, dies nefasti were days on which the courts were closed and the administration of justice was prohibited. On these days, magistrates could not lawfully hear cases, issue judgments, or conduct official legal proceedings. The term stands in contrast to dies fasti, which were the lawful court days on which judicial business could proceed.
The concept carried both religious and administrative dimensions in Roman practice: the calendar was formally divided into categories of days, with dies nefasti designated as off-limits for legal activity, often corresponding to religious observances, festivals, or days of ill omen.
In English legal tradition, the functional equivalent is the dies non juridicus — a day on which no legal business can be transacted. Sunday, Christmas Day, and recognized legal holidays have historically served this role in common law jurisdictions.
Common Confusion
Dies nefasti, dies non, and dies non juridicus are related but not identical concepts. Dies nefasti is the Roman law source term; dies non juridicus is the English law equivalent. Rapalje & Lawrence treat the English term separately under its own entry, signaling that the Roman and common law categories, while functionally parallel, are not technically interchangeable. Researchers encountering dies nefasti in historical sources should not assume a precise mapping onto later English or American legal holidays without checking the specific context. Dies fasti, the opposite category, is the Roman term for days on which courts were open — a distinction critical for any analysis of the Roman calendar's legal structure.
Why It Matters in Research
Dies nefasti appears almost exclusively in Roman law discussions and in English legal sources that were drawing analogies between Roman and common law institutions. It is not an operative term in American or modern English law, but it surfaces in:
Historical treatises and law dictionaries that explain the origins of court holidays, judicial recesses, and the concept of dies non. Writers seeking a learned Latin antecedent for the common law prohibition on transacting legal business on certain days routinely invoked dies nefasti.
Jurisdictional computation problems. Understanding that certain days were categorically excluded from legal computation in Roman practice helps contextualize early common law rules on the counting of time in pleading, limitations periods, and the service of process. When historical sources discuss whether an act performed on a dies non juridicus is void or merely voidable, the Roman framework for dies nefasti is often in the background.
Cross-referencing trap: Rapalje & Lawrence's entry directs readers to dies fasti rather than defining dies nefasti independently, while Black's and Burrill's provide direct definitions. A researcher relying only on Rapalje & Lawrence would need to follow the cross-reference to reconstruct the full meaning. This is a common pitfall when working across the historical dictionary shelf.
The Mackeldey citation (Ferdinand Mackeldey, Compendium of Modern Civil Law, known in English translation as Roman Law) appears in both Black's and Burrill's entries. This treatise is the primary authority being cited for the Roman calendar framework. Researchers following the citation trail should note that Burrill's cites § 35 while Black's cites § 39 — a discrepancy likely reflecting different editions or translations of Mackeldey in circulation at the time of compilation.
Historical Dictionary Support
Black's and Burrill's are in near-complete agreement, offering virtually identical definitions and citing the same Mackeldey authority. The definitions establish two elements: (1) courts were closed, and (2) administration of justice was unlawful. Both dictionaries explicitly link dies nefasti to dies non juridici as the English parallel.
Rapalje & Lawrence takes a different editorial approach, declining to define dies nefasti directly and instead cross-referencing dies fasti. The entry for dies non and dies non juridicus in Rapalje & Lawrence is more developed than in the other sources, providing concrete examples (Sunday, Christmas Day) and a North Carolina case citation for the English-law concept. This suggests Rapalje & Lawrence was more focused on the practical common law application than on the Roman law antecedent.
None of the three historical dictionaries addresses the internal Roman subdivision of dies nefasti into further categories (such as dies nefasti publici versus other subtypes recognized in classical Roman legal scholarship). Researchers needing finer-grained Roman law analysis should move beyond the English-language law dictionaries to civil law treatises, particularly Mackeldey or Mommsen.