Definition
Magnum centum (Law Latin: "great hundred") is an archaic unit of numerical reckoning used in old English legal records meaning 120, rather than the standard 100. Where a document specifies a quantity in magnum centum, the count proceeds by six-score — that is, six groups of twenty — rather than by the familiar decimal hundred. The term distinguishes this inflated reckoning from the ordinary or "small" hundred of 100 units.
Common Language
Modern common usage (Wiktionary): "Hundred" means the cardinal number 100, the natural number following 99.
Historical common usage (Webster's 1913): "Hundred" is defined as ten times ten; a collection or sum of ten times ten units or objects; one hundred also denoted, in some historical contexts, a division of a county in England.
The gap matters here: in ordinary English, past and present, "hundred" unambiguously means 100. In certain medieval and early modern legal instruments, "hundred" could mean 120. A researcher who applies the modern arithmetic meaning without checking whether the document uses magnum centum or the small hundred will misread quantities — potentially by 20 percent — in contracts, grants, tallies, and accounts.
Common Confusion
Magnum centum (120) versus centum (100). The ambiguity was real and recognized in medieval commercial and legal practice. The "great hundred" or "long hundred" of 120 was common in trade contexts involving certain commodities — fish, hides, and other goods counted by the score — before decimal reckoning became standard. A document that says simply "centum" must be read in context; the qualifier magnum is the signal that 120 is intended, but its absence does not guarantee the writer meant only 100.
Why It Matters in Research
This term is a precision trap for anyone working in medieval English records, manorial accounts, royal charters, or early commercial documents. The practical research risks are:
Quantity misreading: Grants, rents, tolls, and commodity tallies expressed in magnum centum will be systematically undercounted by 20 percent if read as ordinary hundreds. A grant of ten magnum centum of herring is 1,200 fish, not 1,000.
Manuscript context dependency: The term does not always appear in its full Latin form. Scribes abbreviated freely, and the "great" qualifier was sometimes omitted when the usage was locally understood. Researchers must attend to the subject matter and the commodity type as independent signals.
Chronological relevance: Magnum centum appears primarily in records from the medieval period through the early modern era. By the time printed legal forms and statutes became standardized, decimal hundreds had largely displaced the great hundred in formal legal instruments, though the long hundred persisted longer in commercial and customary usage. Do not expect to encounter this term in post-seventeenth-century English legal documents without explanation.
Cowell's Interpreter: Burrill cites Cowell, whose Interpreter (1607) is a standard reference for Law Latin terms of this period and is a useful parallel source for confirming the definition in context.
Historical Dictionary Support
Burrill's Law Dictionary provides the core entry: magnum centum is the great hundred, equaling six-score or 120, citing a Charter Roll of 20 Henry III and Cowell. This is consistent with what historical and antiquarian sources record about the long hundred in medieval English commercial and administrative practice. Burrill does not elaborate on which commodities or contexts most commonly used this measure, nor does he address the geographic variation in whether the great or small hundred was the default. The entry is reliable as far as it goes but minimal; researchers needing depth should consult Cowell directly and standard works on medieval English weights and measures.
No other Law Mind shelf dictionary covers this term. Its absence from later dictionaries reflects its obsolescence rather than any doubt about its historical meaning.
Jurisdictional Note
Magnum centum is a feature of English legal and administrative records. Analogous "long hundred" conventions existed in Scandinavian and continental Germanic practice, but the specific Latin term and its documentary contexts are primarily English. Researchers working in Scottish, Irish, or colonial records should verify local usage before assuming the same reckoning applies.