Decan 1 of Cancer

This is the first ten-degree segment of Cancer, the cardinal water sign, spanning 0 to 10 degrees. Its ruler in the Chaldean order of faces is Venus, following the unbroken sequence of the seven planets around the wheel of thirty-six decans. The decans are the oldest layer of astrology, beginning as thirty-six Egyptian star groups whose successive risings served as a calendar and a star-clock, and only later absorbed into the Greek zodiac as ten-degree subdivisions of the signs.

The Golden Dawn, from 1888, mapped the numbered minor cards onto the decans in order; this segment carries the Two of Cups, to which they gave the title Love, its Venus-in-Cancer attribution drawn from the face ruler, Venus in the tender water sign matching the card of union and affection. That tarot correspondence is a modern Western overlay on the ancient decan scheme, not something inherited from Egypt or the Hellenistic astrologers.

The first decan of Cancer runs from 0 to 10 degrees of the sign and is ruled, in the scheme this atlas records, by Venus.

The card on the decan

In the Golden Dawn's assignment this decan carries the Two of Cups. 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 Cancer is a Water sign and takes a card of Cups, and the rank follows the position in the sequence, which puts the two here.

Two ruler schemes, and which one this is

Two schemes for decan rulership are in circulation and they disagree. The one recorded here runs the seven planets in Chaldean order continuously round the circle. The other, the triplicity scheme, gives a sign's three decans to the rulers of the three signs of its own element in order, so the rulers stay inside the element and restart at every sign. Both are attested in the tradition, neither is a corruption of the other, and a reader comparing two books will find them differing here without either being wrong.

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.