Decans in Astrology

The History of Decans

Most people that have done the deep dive into astrology will have noticed that there are two different decan systems. So what is the difference and why do I use the one that I do? Well, that question goes back to the origins of astrology as we know it. The decans are a system that divides each sign by ten degrees, forming the three faces of the signs. We first see this in Egypt where the zodiac was divided into 360° with 36 decans that rule their 10° period. Each decan was associated with a deity and star group containing specific fixed stars that were used to calculate time during the night, with each decan signifying the progression of the hour. 

These decans had a highly religious significance in Egyptian culture and are found on coffin lids as early as 2100 BC, with each decan being associated with a deity and being believed to influence health through cosmic sympathy. After the conquests of Alexander the Great which started in 334 BC, and as Egypt became Hellenized, the 36 decans were synthesized with the system of 12 zodiac signs and seasons developed by the Chaldean priesthood in Babylon that the Greeks had adopted in cohesion with Mesopotamian influence.

During this period of cultural fusion the astrological methods of the Greek, Egyptian, and Mesopotamian cultures combined as astrology became an expression of the theoretical conception of the sky’s structure. Astrology was seen as expressing the divine order of the cosmos that had been a focus of Plato’s thesis, and in this way the myths of the old gods shaped the development of astrology and were transplanted in a systematic way onto the planets and the stars, which were believed to represent the will of the deities. The celestial bodies that all three cultures had worshiped as gods became the cosmic and planetary spheres. This study of the cosmos also in many ways led to the development of modern science and the scientific method, with extreme advances in geometry and trigonometry.   

By the 1st century CE the Chaldean decans had been fully incorporated into the Hellenic astrological tradition and were codified in Ptolemy’s Tetrabiblios in the 2nd century, which shaped astrology as we know it. Ptolemy considered his system a simplification of the Chaldean, Egyptian, and Greek astrological traditions that had preceded him and sought to create a more consistent foundation with principles that are still used. He stressed the importance of using the exact moment of birth for personal astrology and incorporating the place of birth in the casting of natal charts. 

The Chaldean decans begin with Mars in Aries as the domicile planet, and in a nod to the original Egyptian decans align the traditional Saturnian beginning of the Chaldean order in the first decan of Leo, where the heliacal rising of Sirius had begun the Egyptian sequence. This leads to a final decan ruled by Mars in Pisces, and the only disruption in the system with the duplication of Mars rulership on either side of the spring equinox. 

These Chaldean decans were taught by the Greco-Egyptian astrologer known as Taucer of Babylon in the 3rd century, Roman astrologer Firmicus in the 4th century, and the Arabic astrologer Abu Ma’shar in the 9th century. When Abu Ma’shar’s work was translated into Latin during the Renaissance it shaped the astrology of that period, where we see the Chaldean decans recognized as the face of the planets in the five essential dignities. 

During the period of late antiquity we also see the first development of the triplicity system of decans in Indian literature. This method assigns the planetary rulership of each sign based on the planetary ruler of the signs in the same element. Of course the Indian astrologers practiced Vedic astrology which follows very different principles than Western astrology. The triplicity system of decans didn’t enter Western astrology until the 20th century, when they were introduced by British astrologer Alan Leo. This triplicity method has become the preferred method for modern astrologers.

So, since I use the traditional rulerships that have developed in cohesion with Western astrology, I use the Chaldean decans. Indeed, when you begin to dive into the alignments of rulership in traditional Western astrology you can see the extreme effort made to incorporate the different astrological systems, with a two part division of the year being represented through the planetary rulership of the zodiac signs, a three part division of the year as expressed through the repetition of the elements, a four part division of year as expressed through the repetition of the modalities, the twelve part year as expressed through the zodiac signs, and the 36 part division of the year as expressed through the Chaldean decans. 

The Chaldean decans are also the system used in the tarot decan associations of Rosicrucian and founder of the Hermetic Order of the Golden Dawn Macgregor Mathers and codified through the RWS and Thoth tarot decks developed by members of the Golden Dawn. These also used Mathers western interpretation of Kabbalah and the Tree of Life which has been highly criticized and is not a focus of my work. There was also an interesting and similar system of associations between the Chaldean decans and tarot by Papus, but it is the one developed by Mathers that shaped modern tarot as we know it. 

So, in alignment with the most consistent patterns of Western astrological study and scholarship, I use the Chaldean decans and the tarot associations of the Golden Dawn. These form the three faces of each zodiac sign and can lend insight to the focus of natal and transiting planets, and depth to tarot readings. I will list these decans below but if you are interested in a deeper interpretation of the decans please subscribe to our Sun Cycle newsletter here: https://www.naturalmagickcoop.com/products/season-cycle-astrology-sun-planet-and-asteroid-meanings. This week we will be dialing into the decans of Virgo. 

Chaldean Decans and Tarot Associations

Aries

• 1st Decan - Mars - Two of Wands - Dominion
• 2nd Decan - Sun - Three of Wands - Virtue
• 3rd Decan - Venus - Four of Wands - Completion

Taurus

• 1st Decan - Mercury - Five of Coins - Worry
• 2nd Decan - Moon - Six of Coins - Success
• 3rd Decan - Saturn - Seven of Coins - Failure

Gemini

• 1st Decan - Jupiter - Eight of Swords - Interference
• 2nd Decan - Mars - Nine of Swords - Cruelty
• 3rd Decan - Sun - Ten of Swords - Ruin

Cancer

• 1st Decan - Venus - Two of Cups - Love
• 2nd Decan - Mercury - Three of Cups - Abundance
• 3rd Decan - Moon - Four of Cups - Luxury

Leo

• 1st Decan - Saturn - Five of Wands - Strife
• 2nd Decan - Jupiter - Six of Wands - Victory
• 3rd Decan - Mars - Seven of Wands - Valour

Virgo

• 1st Decan - Sun - Eight of Coins - Prudence
• 2nd Decan - Venus - Nine of Coins - Gain
• 3rd Decan - Mercury - Ten of Coins - Wealth

Libra

• 1st Decan - Moon - Two of Swords - Peace
• 2nd Decan - Saturn - Three of Swords - Sorrow
• 3rd Decan - Jupiter - Four of Swords - Truce

Scorpio

• 1st Decan - Mars - Five of Cups - Disappointment
• 2nd Decan - Sun - Six of Cups - Pleasure
• 3rd Decan - Venus - Seven of Cups - Debauch

Sagittarius

• 1st Decan - Mercury - Eight of Wands - Swiftness
• 2nd Decan - Moon - Nine of Wands - Strength
• 3rd Decan - Saturn - Ten of Wands - Oppression

Capricorn

• 1st Decan - Jupiter - Two of Coins - Change
• 2nd Decan - Mars - Three of Coins - Work
• 3rd Decan - Sun - Four of Coins - Power

Aquarius

• 1st Decan - Venus - Five of Swords - Defeat
• 2nd Decan - Mercury - Six of Swords - Science
• 3rd Decan - Moon - Seven of Swords

Pisces

• 1st Decan - Saturn - Eight of Cups - Indolence
• 2nd Decan - Jupiter - Nine of Cups - Happiness
• 3rd Decan - Mars - Ten of Cups - Satiety