The details of purification and expiation--the former serving the interests of the state and its religious needs, the latter intended as a final appeasement of the injured powers of the unseen world--were closely united in practice and are often confused in the accounts which have come down to us. A hard and fast distinction between them cannot be drawn. So much at all events is clear; the expiatory rites indispensable when murder had been committed had the closest possible similarity with the ritual of sacrifice to the gods of the underworld.[167\5] And, in fact, the deities invoked at such rites of expiation--Zeus Meilichios, Zeus Apotropaios, and the rest--belong to the underworld circle of gods.[168\5] To them, instead of the murderer himself, a victim was offered to appease the anger felt by them as the patrons of the departed soul. The Erinyes, too, have sacrifice made to them at expiations[169\5]--everything in these matters is connected with the kingdom of the dead and its inhabitants. But it was the Delphic Oracle that saw to the details of purification and expiation after murder. The necessity of such rights was impressed on men by the example set in the story of Apollo's own flight and purification after the slaying of the earth-spirit at Pytho. These events were symbolically enacted over again regularly every eight years.[170\5] At Delphi, {181} too, according to Aeschylus, Apollo himself purified Orestes the matricide from the pollution of his crime.[171\5] At Athens one of the oldest propitiatory sites was called after one of Apollo's titles, the Delphinion.[172\5] The Oracle must often have directed its inquirers to placate not merely the Heroes, but also the angry souls of murdered (and not heroized) men by means of expiatory sacrifices: as it bade the murderers of Archilochos and the Spartan king Pausanias.[173\5] Propitiatory sacrifice in this sense does not belong to the Apolline cult as an exclusive possession; it belongs, also, to other, mostly lower-world, deities; but it was the Oracle of Apollo that set the seal on its sanctity. At Athens the Exegetai founded under the influence of the Delphic Oracle were the official administrators of this expiatory ritual.[174\5] Plato was certainly following the customs of Greek cities when in the "Laws" he declares that his state shall take its regulations for purification and propitiation from Delphi.[175\5] § 4