Definition
Magna precaria (also rendered magna precaria or "great boon-day") was a term in old English manorial law referring to a great or general reap-day — a customary occasion on which a lord of the manor could call all his villeins and bond tenants together to perform collective harvest labor on his demesne lands. It was one of the more burdensome forms of boon-work, distinguished from lesser or ordinary reap-days by the scale of the obligation and the breadth of those summoned to participate. The tenant had no choice in the matter; attendance and labor were owed as a condition of holding customary land under the lord.
Common Confusion
Magna precaria should not be confused with the ordinary or lesser precaria (sometimes called parva precaria, the "small boon-day"), which imposed a more limited reaping obligation on a smaller number of tenants or for a shorter duration. The distinction mattered in manorial court proceedings when a lord sought to enforce labor services or when a tenant contested the scope of what was owed. Researchers may also encounter precarium in a broader Roman and ecclesiastical law context, where it refers to a revocable grant of land or goods held at another's pleasure — an entirely different concept sharing only the Latin root.
Why It Matters in Research
This term appears almost exclusively in sources dealing with English manorial and feudal tenure before the gradual commutation of labor services into money rents, a process largely complete by the late medieval period. Researchers working with manor court rolls, custumals, extents, and surveys from roughly the twelfth through fifteenth centuries are most likely to encounter magna precaria or its vernacular equivalents. A few navigational cautions:
First, the term is terminologically unstable in the historical record. Scribes recording manorial customs in Latin, Law French, or Middle English used varying forms — "magna precaria," "great boon-day," "great reap," and local dialect equivalents may all refer to the same obligation. Cross-referencing the term against manorial custumals and extents is essential before concluding that any single label maps cleanly onto a single obligation.
Second, the practical content of the obligation varied by manor. The number of days owed, whether food and drink were supplied by the lord, whether the obligation ran with the land or the person, and whether it had been commuted to a money payment by the time of a given document are all questions that cannot be answered from the term alone. The answer lies in the specific custumal or extent for the manor in question.
Third, because labor services of this kind were progressively commuted during the thirteenth and fourteenth centuries, a source dating from before commutation may describe magna precaria as a live obligation, while a later source for the same manor may record it only as a historical curiosity or a nominal money payment. Researchers must be attentive to the date of the source and the date of the practices it describes.
Fourth, magna precaria has essentially no footprint in post-medieval English law or in any common law jurisdiction outside the historical study of English manorial tenure. It does not appear in modern statutory or case law contexts.
Historical Dictionary Support
Black's Law Dictionary (2nd Ed., Supplemental) defines magna precaria concisely as "a great or general reap-day" and attributes the entry to Cowell and Blount — two foundational reference works for early English legal and antiquarian terminology. John Cowell's Interpreter (1607) and Thomas Blount's Nomo-Lexicon (1670) are the natural sources for terms of this vintage and character; both compiled vocabulary drawn from medieval English practice that had already become archaic by their own times. The brevity of Black's entry accurately reflects how little operative legal content the term carried even by the seventeenth century. No significant divergence among historical sources is apparent, which is itself informative: the term was not contested or actively litigated in ways that would have produced competing definitions.
Historical sources are largely silent on the procedural mechanics of how a magna precaria was summoned, enforced, or disputed — researchers needing that level of detail must go beyond legal dictionaries to manorial records and agrarian history scholarship.
Jurisdictional Note
Magna precaria is specific to English manorial tenure and has no equivalent in Scots law, civil law systems, or any modern common law jurisdiction. Its relevance is confined to historical English legal records.