The First Decan of Sagittarius

This is the first ten-degree segment of Sagittarius, the mutable fire sign, spanning 0 to 10 degrees. Its ruler in the Chaldean order of faces is Mercury, following the continuous sequence of the seven planets around the thirty-six decans. The decans are the oldest stratum of astrology, beginning as thirty-six Egyptian stars whose risings marked the ten-day weeks of the year and were absorbed into the Greek zodiac as ten-degree subdivisions only later.

The Golden Dawn of 1888 assigned the thirty-six minor arcana to the decans in order; this segment bears the Eight of Wands, titled Swiftness, its Mercury-in-Sagittarius planet taken from the face ruler, swift Mercury in the far-shooting fire sign matching the card's image of arrows in flight and rapid motion. That tarot correspondence is a modern Western overlay on the far older decan scheme, not a feature of the Egyptian or Hellenistic decan material it was laid upon.