Since each astrological sign has characteristics which are similar to those of a planet, it is said to be in analogy with the planet involved. All signs are ruled by, or under the rulership of a planet. Besides, a sign may be fairly compatible with another planet even if the planet is not its ruler, and conversely, a planet may symbolise values unconnected to those of the sign it tenants, and in such cases, the planet's expression becomes rather negative or less significant.
Depending on its state, a planet is referred to as dignified or debilitated. Five states are possible: rulership, when the planet is in the sign(s) it rules, detriment, exaltation and fall. The fifth state is referred to as peregrine: a planet is peregrine when it is in none of the four states enumerated above. Lastly, it is important to mention that modern astrologers do not agree on the importance of planetary dignities and debilities. Therefore, caution is to be exercised. On Astrotheme, we take them into account, but with moderation, in our astrological reports and our on-line applications.
A planet posited in the sign it rules is said to be in its rulership, or home. Thus, it is able to totally fulfil its role, and it is most likely that its action plays out very positively.
On the contrary, when a planet is in the sign opposite the sign it rules, it is said to be in detriment. Thus, its action is negative, misused, or non-existent or weakened.
A planet in a sign of a similar nature, but which it does not rule, is said to be in exaltation. The planet gets strength and energy from its exaltation, and thus, its influence is positive.
A planet in the sign opposite the sign of its exaltation is said to be in fall. Therefore, contrarily to the exaltation, the planet loses its strength and influence.
When a planet is in none of the enumerated four states, it is in a peregrine state, or it is a peregrine planet.
In two cases out of three, planets are peregrine, and the aspects they form with other planets or angles are even more determining.
This is an important remark that is worth underlining. More and more often, modern astrology decreases the influence of rulerships and pays more attention to aspects.
Statistical observations and practical experiences show that even when a planet is in detriment or in fall, most often, it can play out positively, provided it is well-aspected.
Therefore, caution is to be exercised as you learn those rulership and debility rules that remain nonetheless important.
Here is the rulership list:
Rulership in Leo, exaltation in Aries, detriment in Aquarius, fall in Libra.
Rulership in Cancer, exaltation in Taurus, detriment in Capricorn, fall in Scorpio.
Rulership in Gemini and Virgo, exaltation in Virgo too, detriment in Sagittarius and Pisces, fall in Pisces too.
Rulership in Taurus and Libra, exaltation in Pisces, detriment in Scorpio and Aries, fall in Virgo.
Rulership in Aries and Scorpio, exaltation in Capricorn, detriment in Libra and Taurus, fall in Cancer.
Rulership in Sagittarius and Pisces, exaltation in Cancer, detriment in Gemini and Virgo, fall in Capricorn.
Rulership in Capricorn and Aquarius, exaltation in Libra, detriment in Cancer and Leo, fall in Aries.
Rulership in Aquarius, exaltation in Scorpio, detriment in Leo, fall in Taurus.
Rulership in Pisces, exaltation in Leo (or in Cancer, depending on authors), detriment in Virgo, fall in Aquarius (or in Capricorn, depending on authors).
Rulership in Scorpio, exaltation in Aries (or in Pisces, depending on authors), detriment in Taurus, fall in Libra (or in Virgo, depending on authors).