It is not by their faithfulness to Plato’s doctrine, which in truth they alter, but by the mere logic of their system that the last Greek philosophers are led to admit what their predecessors rejected. Sometimes, more or less unconsciously, they were under a religious influence. The Platonist Celsus believed in the eternal pains of hell but invoked only the authority of “mystagogues and theologians” in support of this article of faith.[214] The opposition between the obscure retreats of the Manes and the bright dwellings of Olympus is old, and naturally became prominent as the belief spread, first that heroes, and afterwards that all virtuous spirits, rose to the eternal spaces.[215] But the religion which formulated the strictly consequent doctrine of an absolute antithesis between the luminous kingdom where the divinities and the beneficent genii were seated, and the dark domain of the Spirit of Evil and his perverse demons, was Persian Mazdeism. The resplendent heights where the gods had their thrones were to be after death the abode of those who had served piously. On the other hand, those who had contributed to increase evil on the earth, were to be flung into the murky abysses in which Ahriman reigned. Iranian dualism imposed this eschatological conception on a section of Alexandrian Judaism; it was admitted by many Pythagoreans, then by the gnostic sects and later by Manicheism. But above all it was widely propagated under the Roman Empire by the mysteries of Mithras. We find then put forth the doctrine that the demons are divided into two armies, incessantly at war with each other, one good and one evil. The good army is subject to celestial powers and comes down to earth to give succour and support to the faithful. The evil army obeys an anti-god (ἀντίθεος) and issues from the bowels of the earth in order to scatter misery, sin and death among men.[216] The souls of the dead become like one or the other of these two opposing classes of demons. When they are virtuous and pure they rise to the luminous ether where dwell the divine spirits. If, on the contrary, they are vicious and defiled they go down into the underground depths where the Prince of Darkness commands; like the maleficent demons who people this hell they suffer and cause to suffer.