Decan 2 of Gemini

This is the second ten-degree segment of Gemini, the mutable air sign, spanning 10 to 20 degrees. Its ruler in the Chaldean order of faces is Mars, following the continuous planetary assignment around the thirty-six decans. Historically the decan is the oldest layer of astrology: the thirty-six decans were Egyptian star groups, a calendar and a night-clock older than the zodiac itself, later folded into the twelve signs three to a sign and given planetary rulers by the Chaldean order.

The Golden Dawn, from 1888, mapped the numbered minor cards onto the decans; this segment carries the Nine of Swords, to which they gave the title Cruelty, its Mars-in-Gemini attribution taken directly from the face ruler, the harsh Martian force in the airy mental sign matching the card's image of anguish. That tarot layer is a modern Western construction over the ancient decan scheme, useful for divination but not ancient.

The second decan of Gemini runs from 10 to 20 degrees of the sign and is ruled, in the scheme this atlas records, by Mars.

The card on the decan

In the Golden Dawn's assignment this decan carries the Nine of Swords. The mapping is one to one and exhaustive: the thirty-six small cards numbered two to ten across the four suits match the thirty-six decans exactly, taken in order from the Two of Wands at the first decan of Aries. The suit follows the sign's element, so Gemini is a Air sign and takes a card of Swords, and the rank follows the position in the sequence, which puts the nine here.

Three layers, three periods

The decans are Egyptian: thirty-six star groups whose successive risings told the hours of the night, attested on coffin lids from the Middle Kingdom onward. The division of the zodiac into thirty-six ten degree segments with planetary rulers is Hellenistic, several centuries later, and it is a different object that inherited the name and the number. The tarot assignment is later again, and belongs to the Hermetic Order of the Golden Dawn in the late nineteenth century. None of it is Egyptian, and this atlas records the three as three.

What the atlas is recording

The degrees and the ruler are the attributions this atlas holds for this decan, and the card is the Golden Dawn's. All of them are traditions with variants rather than settled facts, and the decan itself, as a ten degree segment of a sign, is the only part that is simply arithmetic.