Virgo is the sixth sign, mutable, earthy and ruled by Mercury, with Mercury also taking its exaltation there, the only case in the classical scheme where a planet holds both dignities in the same sign. It closes the summer quarter and stands at the harvest, and the traditional meanings follow directly from that: separation of the good from the useless, measurement, sorting, service, and the labour by which what has grown is made usable. The Mercurial rulership here works through earth rather than air, so the sign is read for practical discrimination and craft rather than for speech. In medical astrology Virgo governs the bowels and the process of assimilation, which is the same idea of sorting applied to the body, and the sign is classed among the barren signs in questions of fertility.
Virgo's three decans run Sun, Venus, Mercury, continuing the Chaldean sequence from Leo's final Mars decan. Virgo's triplicity follows the earth assignment, Venus by day and the Moon by night in both the Ptolemaic and the Dorothean tables, one of the three elements, with fire and air, where the classical authorities are in full agreement; only the water triplicity, covered under Cancer, Scorpio and Pisces, shows the genuine split between Ptolemy's own table and the version Lilly inherited from Dorotheus. Some Renaissance sources also give Virgo a secondary night rulership by Mercury alone in a simplified two-planet scheme, a further variant that modern textbooks do not always flag as one among several competing versions.