Each Planet Rules Two Signs (Except Sun and Moon)

Before the discovery of Uranus, Neptune, and Pluto, astrologers assigned planetary rulerships to the 12 signs using only 7 visible celestial bodies. Each planet except the Sun and Moon ruled two opposite signs.

For example, Mercury rules both Gemini and Virgo, Venus rules Taurus and Libra, and Mars rules Aries and Scorpio. This created a balanced system.

When the outer planets were discovered, they were assigned as modern rulers of Scorpio (Pluto), Aquarius (Uranus), and Pisces (Neptune), though some astrologers still use the traditional rulerships.