sentences:  It had historically been used as a beacon to warn of invasion.Its enormous walls were created in the 18th century but remnants of the central keep and other features can still be seen.William de Home, son of Sir Patrick de Greenlaw (a younger son of Cospatric I, Earl of Dunbar), acquired the lands of Home in the early 13th century through marriage to his cousin Ada (the daughter of Patrick I, Earl of Dunbar).