Frequently asked questions

Traditional Decans (based on triplicity)

We call this method "traditional" because in modern astrology it is the most common one and therefore "has tradition". More correctly, it should be called "decans according to triplicity". The rulers of the decans are derived from the rulers of the signs of the same element (= triplicity, trigon, trine). The decan rulers of Aries are the rulers of Aries, Leo, and Sagittarius (thus Mars, the Sun, and Jupiter); the decan rulers of Taurus are the rulers of Taurus, Virgo, and Capricorn (thus Venus, Mercury, and Saturn); etc. etc.

The new planets Uranus, Neptune, and Pluto are also accepted as sign rulers in this system. However, if the option "Uranus-Pluto off" is chosen, then the classical sign rulers are used in their place, namely Saturn, Jupiter, and Mars.

This method of decans is found in Indian texts of Late Antiquity. It seems to have been introduced in western Astrology only in the 20th century by the British astrologer Alan Leo.

In this system, the decans have the following rulers:

• Aries: Mars Sun Jupiter
• Taurus: Venus Mercury Saturn
• Gemini: Mercury Venus Uranus/Saturn
• Cancer: Moon Mars Neptune/Jupiter
• Leo: Sun Jupiter Mars
• Virgo: Mercury Saturn Venus
• Libra: Venus Uranus/Saturn Mercury
• Scorpio: Pluto/Mars Neptune/Jupiter Moon
• Sagittarius: Jupiter Mars Sun
• Capricorn: Saturn Venus Mercury
• Aquarius: Uranus/Saturn Mercury Venus
• Pisces: Neptune/Jupiter Moon Pluto/Mars

Chaldean Decans

With this method, the rulers of the decans follow the order of the so-called "Chaldean planetary order", which was derived from the geocentric speeds of the planets:

Saturn - Jupiter - Mars - Sun - Venus - Mercury - Moon

The method was taught by the Greco-Egyptian astrologer Teucer "of Babylon" (3rd cent. CE) and the Roman astrologer Firmicus Maternus (4th cent. CE, Mathesis II.4). The system was transmitted to modern European astrology via the Arabic astrologer Abu Ma'shar, whose work was translated into Latin during the Renaissance.

According to this system, the decans have the following rulers:

• Aries: Mars Sun Venus
• Taurus: Mercury Moon Saturn
• Gemini: Jupiter Mars Sun
• Cancer: Venus Mercury Moon
• Leo: Saturn Jupiter Mars
• Virgo: Sun Venus Mercury
• Libra: Moon Saturn Jupiter
• Scorpio: Mars Sun Venus
• Sagittarius: Mercury Moon Saturn
• Capricorn: Jupiter Mars Sun
• Aquarius: Venus Mercury Moon
• Pisces: Saturn Jupiter Mars

Decans of Manilius

With this method, a zodiac sign is assigned to each decan, in agreement with the order of the signs in the zodiac: The first three signs Aries, Taurus and Gemini are assigned to the decans of Aries, the next three signs, Cancer, Leo, and Virgo, are assigned to the decans of Taurus, etc. etc.

This method first appears in the work of the Roman astrologer Manilius (1st cent. CE; Astronomica, IV.312ff.).

In this system the decans have the following assignments:

• Aries: Aries Taurus Gemini
• Taurus: Cancer Leo Virgo
• Gemini: Libra Scorpio Sagittarius
• Cancer: Capricorn Aquarius Pisces
• Leo: Aries Taurus Gemini
• Virgo: Cancer Leo Virgo
• Libra: Libra Scorpio Sagittarius
• Scorpio: Capricorn Aquarius Pisces
• Sagittarius: Aries Taurus Gemini
• Capricorn: Cancer Leo Virgo
• Aquarius: Libra Scorpio Sagittarius
• Pisces: Capricorn Aquarius Pisces

Egyptian Terms

Chaldean Terms

Attention! With night births, Mercury and Saturn are exchanged in this system.

Ptolemean Terms (Lilly)

Ptolemean Terms (Houlding)

Ptolemaean Terms according to Deborah Houlding, see explanations further below.

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