Astronomicon, Book I

287-296 Three squares are similarly inscribed in the circle, and form the following tetragons of signs.

1. Aries Cancer Libra Capricornus.
2. Taurus Leo Scorpius Aquarius.
3. Gemini Virgo Sagittarius Pisces.

A circular diagram of the zodiac signs. The twelve symbols of the zodiac are arranged around the perimeter of a circle: Cancer (top), Gemini, Taurus, Aries, Pisces, Aquarius, Capricorn (bottom), Sagittarius, Scorpio, Libra, Virgo, and Leo. Within the circle, three squares are inscribed. Each square connects four signs at 90-degree intervals. The squares are marked with small numbers 1, 2, and 3 near the signs of Aries, Taurus, and Gemini respectively to identify the groups listed in the text.

These three tetragons, of which Manilius speaks at length in verses 654-672, are identical with the tropika [tropical], the stereā [solid], and the disōma [bicorporeal], which I enumerated at 157-196.

Gemin. 2 16 (quoted in my note on verse 290), Firm. II 22 5.

297-351 Now follows a long digression in which readers learning astrology before they have learnt arithmetic are put on their guard against a puerile miscalculation. They must not suppose that the side of a trigon consists of 5 whole signs; for 5 x 3 = 15, and all the signs of the zodiac are only 12. 12 ÷ 3 = 4; therefore 4 signs, or their equivalent, compose the side of a trigon. The reckoning, in fact, had better not be made by signs, signiliter, zōdiakōs [zodiacally], but by degrees of the circle, partiliter, moirikōs [by degrees]: these are 360, therefore the side of a trigon contains 120 and no more, and should be measured, not from sign to sign, but from point to point, — e.g. from the 15th point of Aries to the 15th of Leo. So also with