A practice is assigned to the Magi by many classical and ecclesiastical writers, which, if it were truly charged on them, would leave a very dark stain on the character of their ethical system. It is said that they allowed and even practised incest of the most horrible kind--such incest as we are accustomed to associate with the names of Lot, OEdipus, and Herod Agrippa. The charge seems to have been first made either by Xanthus the Lydian, or by Ctesias. It was accepted, probably without much inquiry, by the Greeks generally, and then by the Romans, was repeated by writer after writer as a certain fact, and became finally a stock topic with the early Christian apologists. Whether it had any real foundation in fact is very uncertain. Herodotus, who collects with so much pains the strange and unusual customs of the various nations whom he visits, is evidently quite ignorant of any such monstrous practice. He regards the Magian religion as established in Persia, yet he holds the incestuous marriage of Cambyses with his sister to have been contrary to existing Persian laws. At the still worst forms of incest of which the Magi and those under their influence are accused, Herodotus does not even glance. No doubt, if Xanthus Lydus really made the statement which Clemens of Alexandria assigns to him, it is an important piece of evidence, though scarcely sufficient to prove the Magi guilty. Xanthus was a man of little judgment, apt to relate extravagant tales; and, as a Lydian, he may have been disinclined to cast an aspersion on the religion of his country’s oppressors. The passage in question, however, probably did not come from Xanthus Lydus, but from a much later writer who assumed his name, as has been well shown by a living critic. The true original author of the accusation against the Magi and their co-religionists seems to have been Ctesias, whose authority is far too weak to establish a charge intrinsically so improbable. Its only historical foundation seems to have been the fact that incestuous marriages were occasionally contracted by the Persian kings; not, however, in consequence of any law, or religious usage, but because in the plenitude of their power they could set all law at defiance, and trample upon the most sacred principles of morality and religion.