Under the influence of expiatory rites, which were zealously practised even by the ancient mystery cults, these two worlds, the subterranean hell and the celestial paradise, were supplemented by a third region. This development was also apparently of Iranian origin. The region was held to be a place of purification, where the soul of the sinner might be prepared, through transitory punishments and primarily through lust rations, for entrance into the heavenly realm. Purgatorial lustration, after the pattern of terrestrial cult ceremonies, was believed to be effected by means of fire, this being regarded as the most potent lustrical agency, and as combining the function of punishment with that of purification. Dante's" Divine Comedy" presents a faithful portrayal of these conceptions as they were finally developed by the religious imagination of medireval Christianity out of a mass of ideas which go back, in their beginnings, to a very ancient past, but which continually grew through immanent psychological necessity. Dante's account of the world beyond incorporates a further element. It tells of a guide, by whom those exceptional individuals who are privileged to visit these realms are led, and by whom the various souls are assigned to their future dwelling-places. The first of the visitors to Hades, Hercules, was accompanied by deities, by Athena and Hermes. Later it was one of the departed who served as guide. Thus, Virgil was conducted by his father, and Dante, in turn, was led by Virgil, though into the realms of blessedness, closed to the
heathen poet, he was guided by the transfigured spirit of Beatrice. The rOle of general conductor of souls to the realms of the underworld, however, came to be given to Hermes, the psychopomp. Such is the capacity in which this deity appears in the Odyssey, in an exceedingly charming combination of later with \'ery ancient soul-conceptions. After Odysseus has slain the suitors, Hermes, with staff in hand, leads the way to the underworld, followed by the souls of the suitors in the form of twittering birds.