The First Decan of Taurus

This is the first ten-degree segment of Taurus, the fixed earth sign, spanning 0 to 10 degrees. Its ruler in the Chaldean order of faces is Mercury, following the continuous assignment of the seven planets to the thirty-six decans around the zodiac. The decans are the most ancient layer of the tradition, beginning as thirty-six Egyptian star groups that rose in succession to divide the year into ten-day weeks and the night into hours, and were absorbed into the Greek zodiac as ten-degree arcs only in the last centuries BCE.

The Golden Dawn, from 1888, mapped the numbered minor cards onto the decans in order; this segment carries the Five of Coins, to which they gave the title Worry, its Mercury-in-Taurus attribution taken directly from the face ruler. That tarot layer is a modern Western construction laid over the older decan scheme, not a feature of the Egyptian or Hellenistic material.