A mansion is a large dwelling house. The cited article says the word itself derives through Old French from the Latin mansio, meaning dwelling, an abstract noun derived from the verb manere, to dwell, and that the English word manse originally defined a property large enough for the parish priest to maintain himself, whereas a mansion is usually no longer self-sustaining in this way, compare a Roman or medieval villa. It adds that manor comes from the same root, territorial holdings granted to a lord who would remain there, and that after the fall of Rome the practice of building unfortified villas ceased. Buildings recorded in the atlas as mansions are grouped under this concept.