A Castellan is an alternate title for a Chatelaine. In Ealdormere, it is typically used as a masculine title.
A castellan (from the Latin Castellanus, derived from castellum, “castle) is the title used in Medieval Europe for an appointed official, a governor of a castle and its surrounding territory referred to as the castellany. Other forms of this title include Constable, such as the Constable of the Tower of London, or the Constable of France.
Usually the duties of a castellan consisted of military responsibility for the castle's garrison, maintaining defences, and protecting the castle's lands; combined with the legal administration of local lands and workers including the castle's domestic staff. A castellan could exercise the power of the “ban” – that is, to hear court cases and collect fines, taxes from residents, and muster local men for the defence of the area or the realm.