Tetrabiblos and Centiloquy

by the triangular, square, and also hexagonal figures original: "trigonā tetragonā quoqʒ exagonā" referring to the trine (120°), square (90°), and sextile (60°) aspects. However, those parts which we find cannot be associated in these ways are those between which one or five signs are contained. This is because those parts between which there is one sign do not "behold" each other The "inconjunct" or "alien" signs, for they are placed obliquely to one another. Furthermore, those parts between which five signs are located do not divide the circle into equal parts.

¶ Chapter 18. On the houses of the 7 wandering stars and the sun & moon.

Parts of the circle of signs, which are called houses, triplicities, exaltations, and terms dignities: various ways a planet gains strength by being in a specific zodiac sign, are likened to the seven planets in those places where they have some similarity or dignity. The nature of the houses is as I shall subjoin: since, therefore, of the twelve signs, two are northern—namely those which are closest to the place of our zenith the point directly overhead and which for that reason generate heat—which are Cancer and Leo, these were attributed as houses to the two greatest and most worthy luminaries. They placed the sign of Leo, which is masculine, as the house of the Sun. But the sign of Cancer, which is feminine, they established as the house of the Moon. Therefore, they called the half of the circle which is from Leo to Capricorn "solar." The other half, which is from Aquarius to Cancer, they called "lunar." Thus, in each of the two halves of the circle—the solar and the lunar—each of the planets might dwell in a house suitable to it according to the order of their spheres and natures.

¶ For this reason, because Saturn is naturally cold and contrary to heat, and his heaven is higher and more remote from the luminaries, they assigned to him two signs, Capricorn and Aquarius, which are in opposition to Cancer and Leo. This is because these two, namely Capricorn and Aquarius, are cold and wintry, and also because the affinity of figures created by opposition is not favorable in misfortune Saturn is the "Greater Malefic," and the 180° opposition is considered a harsh aspect.

¶ But because Jupiter is of a temperate complexion and is carried beneath the sphere of Saturn, the two signs which follow Capricorn and Aquarius—which are Sagittarius and Pisces—are attributed to him. This is because they produce winds and compel things to rise; and they are at a trine distance 120 degrees from the houses of the luminaries, which is a distance suitable for the fortunes Jupiter is the "Greater Benefic".

¶ Next, because Mars naturally dries, and his sphere revolves beneath the sphere of Jupiter, they gave him the two signs located after the lodgings of Jupiter: these are Aries and Scorpio, whose distance from the houses of the luminaries is square 90 degrees, just as fits a destructive and contradictory heat, which is likened to the nature of Mars.

¶ To the star of Venus, because she is of a temperate complexion and revolves beneath the sphere of Mars, the two signs following the habitations of Mars are attributed—Taurus and Libra—because they cause things to rise; and their distance from the houses of the luminaries is fertile, which is a distance of similarity and suitability; and also because Venus is never found more than two signs distant from the Sun.

¶ Likewise, since of the wandering stars Mercury remained, who in neither of the two parts is ever distant from the Sun by more than the space of one sign, and is carried beneath the other stars, the two remaining signs were given to him, which are located after the places of the luminaries: Gemini and Virgo.

¶ Chapter 19. On the triplicities and their lords.

The affinities of the triplicities triplicity: a group of three zodiac signs belonging to the same element (Fire, Earth, Air, Water) with the planets are as follows. Since, therefore, the figure of an equilateral triangle is in itself equal and suitable, and because the three [parts] of the circle are bounded...