Definition
In old English law, the keeper or constable of a castle. The castellanus was the officer charged with custody and governance of a castle, typically holding that position by royal grant or feudal appointment. The term is essentially synonymous with castellain or castellan. In its secondary usage, castellanus (or castellarium) also referred to the precinct or territorial jurisdiction attached to a castle — the geographic and legal domain within which the castle's authority operated.
Common Language
Modern common usage (Wiktionary): In meteorology, "castellanus" designates a cloud species characterized by vertical, crenellated formations resembling castle battlements, associated with cirrus, cirrocumulus, altocumulus, and stratocumulus genera. In non-technical usage, it appears as an alternative form of "castellan," meaning the keeper of a castle.
Historical common usage (Webster's 1913): Not independently entered; derived from the Latin castellum (castle), with the English form "castellan" denoting the governor or constable of a castle.
The gap between common and legal meaning is modest but worth noting: ordinary usage treats "castellan" as a simple historical title with no legal weight. In medieval English law, however, the office carried enforceable jurisdictional authority — custody of a castle meant custody of a defined territory and, often, the legal processes running within it. The meteorological sense is entirely unrelated and presents no confusion in legal research contexts.
Why It Matters in Research
CASTELLANUS is a term of purely historical significance; it does not appear in modern statutory or common law. Researchers will encounter it almost exclusively in medieval English legal records, land grants, feudal tenure documents, and chronicles. Several research traps are worth flagging:
First, the term doubles as both a personal office (the officer) and a territorial concept (the precinct, via castellarium/castellatus). Early sources conflate these senses, and a document referencing castellanus may be describing a person, a jurisdictional boundary, or both. Black's 2nd edition is more explicit than the 1st in distinguishing the territorial sense.
Second, the office of castellanus intersects heavily with feudal tenure research. Castles were frequently held by serjeanty or knight-service, and the castellanus's authority derived from and was limited by the terms of the original royal or baronial grant. Researchers tracing title chains or manorial jurisdiction will need to read castellanus alongside terms like constabularius, custos, and the broader framework of castle-guard tenure.
Third, jurisdictional records attached to specific castles (castellaria) can be scattered across different document classes — Patent Rolls, Close Rolls, inquisitions post mortem — and the term may appear in Latin forms that indexers do not consistently normalize. Searching variants (castellain, castellan, castellania, castellarium) is advisable.
Historical Dictionary Support
Both Black's editions agree on the core definition: the castellanus is the keeper or constable of a castle, citing Spelman's Glossarium Archaiologicum as authority. The 2nd edition usefully adds the related entry castellarium/castellatus — the precinct or jurisdiction of a castle — citing Blount's Nomo-Lexicon, and marks what the 1st edition left implicit: that the term carries not just a personal but a territorial legal meaning.
Neither edition contextualizes the office within the feudal tenure system or explains how the position was created, transferred, or extinguished — significant gaps for researchers working with primary medieval sources. Spelman and Blount remain the appropriate deeper references; Du Cange's Glossarium Mediae et Infimae Latinitatis provides further Latin-language context for researchers working with continental or ecclesiastical records where cognate terms appear.
Jurisdictional Note
The term is specific to English and Anglo-Norman feudal law, though cognate offices (châtelain in French, Burgvogt in German) appear throughout medieval European legal systems. Researchers working with Scottish or Irish records will encounter distinct but related institutional frameworks, as castle jurisdiction operated somewhat differently under those legal traditions.