Decimation

Definition

Decimation — epidekateuō (Greek ἐπιδεκατεύω, "to be tenth over") — is the square cast specifically from the tenth sign counted from a planet: the superior, dominating square, set against the inferior square from the fourth. The relationship is directional. Which body holds the tenth-place position, looking down on the other, is the whole point — direction is what separates it from a bare ninety-degree aspect.

In Tradition

Hephaistio uses the term in his marriage doctrine for the dignifying tenth-position aspect. Gramaglia's footnote fixes the sense: to decimate is to throw the dominating square at a body from the tenth sign above it. Take Hephaistio's example. Venus is in a benefic's bounds or signs; she decimates the Moon and is in turn decimated by Jupiter — Venus standing tenth from the Moon and fourth from Jupiter. That configuration foretells the happiest and most child-bearing marriage. The doctrine carries the canonical contrast between the dominating square from the tenth and the overcome square from the fourth.

In Practice

When you read a square, note its direction. Count the signs: the planet ten signs along — a quarter-turn in the order of the zodiac, in the position above — is the one doing the decimating, the dominating party. The body squared from the fourth is the overcome one. So with Venus tenth from the Moon, Venus dominates the Moon; with Jupiter tenth from Venus, Jupiter dominates Venus in turn. Treat decimation as overcoming-by-square from the tenth, not as a bare aspect — the direction is what turns a plain square into a verdict.

Historical Origin

The term is used and defined in Hephaistio of Thebes, Apotelesmatics Book III (chapter 9, section 17; in Benjamin Dykes' edition, p. 77, with footnote 217, trans. Eduardo Gramaglia), where Gramaglia glosses epidekateuō as throwing the dominating square down from the tenth sign, illustrated by the Venus-Moon-Jupiter marriage configuration.

Etymology

Origin: Greek. Meaning: to be tenth over; to dominate a body by a square from the tenth sign above it.

Further Reading

• Hephaistio of Thebes, Apotelesmatics Book III
• Chris Brennan, Hellenistic Astrology