A castellan 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. The title of governor is retained in the English prison system, as a remnant of the medieval idea of the castellan as head of the local prison. The word stems from the Latin Castellanus, derived from castellum "castle". Sometimes also known as a constable of the castle district, the Constable of the Tower of London is, in fact, a form of castellan, with representative powers in the local or national assembly. A castellan was almost always male, but could occasionally be female, as when, in 1194, inherited her father's castellany of Bourbourg upon the death of her brother, Roger. Similarly, Agnes became the castellan of Harlech Cast