Ruling planet

In astrology, a planet's domicile (or less commonly house, not to be confused with the astrological house system) is the zodiac sign over which it has rulership. This is a separate concept from the houses of the horoscope. A planetary ruler is given to each sign, over which the planet is said to have a more powerful influence when positioned therein. A planet is considered to be in domal dignity when it is positioned in the sign it rules. This is the strongest of the five essential dignities of a planet.

The assignments of the ruling planets appear to be based upon the Northern Hemisphere seasons, as the sun (Sol) and the moon, the principal bearers of light and heat, were awarded to Leo and Cancer, respectively, since the months the sun passed through these signs (in ancient times) were the warmest and had the longest days.

Conversely, Saturn, the most distant (and hence the "coldest") of the planets known to ancients, was accorded the rulership of Aquarius and Capricorn, the signs opposite Leo and Cancer, respectively.

Jupiter, being next farthest away, was given the signs on either side of Aquarius and Capricorn (Pisces and Sagittarius), and Mars, next in order, received the next two (Aries and Scorpio).

Since Mercury never appears more than one sign from the sun in either direction, it was deemed to rule the two signs on either side of Leo and Cancer (Virgo and Gemini), and since Venus can never be found more than two signs from the Sun, it obtained the rulership of Libra and Taurus.

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