The Second Decan 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.