Definition
In feudal and old English law, a *dugatus* is a duchy — that is, the dignity, rank, or territorial dominion associated with the title of duke. The term encompasses both the honorific status of the duke and the lands or jurisdiction over which that ducal authority extends.
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Why It Matters in Research
Dugatus is pure Latin legal vocabulary of the feudal period and will appear almost exclusively in medieval Latin documents, charters, writs, and treatises. Researchers working in pre-modern English land law, peerage records, or crown grants should treat the term as a synonym for "duchy" in context, but should note that it carries the double meaning of both the personal dignity (the rank itself) and the territorial unit. These two dimensions were legally distinct: a duke's dignity could theoretically survive the loss of the land, and conversely, certain duchies existed as administrative or revenue territories distinct from the holder's personal title.
The most practically significant dugatus in English legal history is the Duchy of Lancaster, which retained (and continues to hold) a distinct legal identity separate from the Crown even after the duchy's lands merged with royal holdings. Researchers tracing property or jurisdictional questions touching the Duchy of Cornwall or Duchy of Lancaster should look for both the Latin form *dugatus* and its vernacular equivalents in period sources.
Because this term appears only in Black's supplemental material and not in the main body of standard editions, it is likely to be absent or very thinly treated in other reference works. Do not expect Bouvier, Burrill, or Tomlin to provide meaningful elaboration.
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Historical Dictionary Support
Black's Law Dictionary (2nd Ed., Supplemental) provides the only definition in the Law Mind corpus: "In feudal and old English law. A duchy, the dignity or territory of a duke." This is characteristically terse. The entry does no work to distinguish the personal dignity from the territorial aspect, and it offers no guidance on how the concept interacted with the broader feudal hierarchy — where the duchy sat above a county (*comitatus*) and below a kingdom in the gradation of territorial units.
No other shelf source in the corpus elaborates on *dugatus* as a discrete entry, which itself tells the researcher something: the term was functional Latin used in instruments and pleadings rather than a term of art requiring doctrinal definition. Historical dictionaries of law Latin (such as Du Cange's *Glossarium Mediae et Infimae Latinitatis*, outside this corpus) would be the natural next resource for deeper philological treatment.
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Jurisdictional Note
The term is specific to English and broader feudal European legal traditions. It has no operative meaning in modern U.S. law. English law retains the duchy as a living institution (Duchy of Lancaster, Duchy of Cornwall), but the Latin form *dugatus* is exclusively a historical research term.
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