Ptolemy's Tetrabiblos: Book the First: Chapter XX. Houses of the Planets

THOSE stars which are denominated planetary orbs have particular familiarity with certain places in the zodiac, by means of parts designated as their houses, and also by their triplicities, exaltations, terms, and so forth.

The nature of their familiarity by houses is as follows:

Cancer and Leo are the most northerly of all the twelve signs; they approach nearer than the other signs to the zenith of this part of the earth, and thereby cause warmth and heat: they are consequently appropriated as houses for the two principal and greater luminaries; Leo for the Sun, as being masculine; and Cancer for the Moon, as being feminine. It has hence resulted, that the semicircle from Leo to Capricorn has been ordained solar, and the semicircle from Aquarius to Cancer, lunar; in order that each planet might occupy one sign in each semicircle, and thus have one of its houses configurated with the Sun and the other with the Moon, conformably to the motions of its own sphere, and the peculiar properties of its nature.