Sagittarius is the ninth sign, mutable, fiery and ruled by Jupiter, and in the classical scheme it has no exaltation. It closes the autumn quarter and is read for expansion, distance and the pursuit of what lies beyond present reach: long journeys, foreign places, law, philosophy and religion, all of which belong to the ninth house of the natural chart and to Jupiter as its ruler. The figure is a bicorporeal or double-bodied sign, part human and part animal, and the classical sources make something of that division, treating the sign as one in which reason and appetite pull in the same direction rather than against each other. Its fiery mutability is read as movement outward rather than the settled heat of Leo or the ignition of Aries.
Sagittarius's three decans run Mercury, Moon, Saturn, continuing the sequence from Scorpio's final Venus decan. As a fire sign, Sagittarius's triplicity is Sun by day and Jupiter by night, agreeing exactly across the Ptolemaic and Dorothean tables along with Aries and Leo, its fellow fire signs; here too the classical authorities concur, and the dispute recorded under Cancer, Scorpio and Pisces is confined to water alone. Firmicus Maternus, writing in the fourth century, gives Sagittarius an unusually detailed treatment of professions, linking the sign to hunters, athletes and those who work with horses, a occupational reading typical of how the Hellenistic sources translated a sign's mythic figure into a catalogue of trades.