In old astrological writings (e.g. William Lilly), "house" could also be used as a synonym for domicile or rulership, as in the sentence "The Moon has its house in Cancer" meaning that Cancer is ruled by the Moon. It may be helpful to think of a ruling planet, in this case the Moon, as the "owner of the 4th House", and the sign, "e.g." Cancer, as the CEO or landlord who runs the house. In an individual horoscope, whatever planet occupies any given house can be thought of as the house's tenant. (See Rulership section below.)