It is impossible to say how this development took place. We have evidence, however, that at a period considerably anterior to the commencement of the Median Empire, Dualism, not perhaps in its ultimate extravagant form, but certainly in a very decided and positive shape, had already been thought out and become the recognized creed of the Iranians. In the first Fargard, or chapter, of the Vendidad--the historical chapter, in which are traced the only movements of the Iranic peoples, and which from the geographical point whereat it stops must belong to a time when the Arians had not yet reached Media Magna---the Dualistic belief clearly shows itself. The term Angro-mainyus has now become a proper name, and designates the great spirit of evil as definitely and determinately as Ahura-mazda designates the good spirit. The antagonism between Ahura-mazda and Angro-mainyus is depicted in the strongest colors; it is direct, constant and successful. Whatever good work Ahura-mazda in his benevolence creates, Angro-mainyus steps forward to mar and blast it. If Ahura-mazda forms a “delicious spot” in a world previously desert and uninhabitable to become the first home of his favorites, the Arians, Angro-mainyus ruins it by sending into it a poisonous serpent, and at the same time rendering the climate one of the bitterest severity. If Ahura-mazda provides, instead of this blasted region, another charming habitation, “the second best of regions and countries,” Angro-mainyus sends there the curse of murrain, fatal to all cattle. To every land which Ahura-mazda creates for his worshippers, Angro-mainyus immediately assigns some plague or other. War, ravages, sickness, fever, poverty, hail, earthquakes, buzzing insects, poisonous plants, unbelief, witchcraft, and other inexpiable sins, are introduced by him into the various happy regions created without any such drawbacks by the good spirit; and a world, which should have been “very good,” is by these means converted into a scene of trial and suffering. The Dualistic principle being thus fully adopted, and the world looked on as the battle-ground between two independent and equal powers engaged in perpetual strife, it was natural that the imagination should complete the picture by ascribing to those superhuman rivals the circumstantials that accompany a great struggle between human adversaries. The two kings required, in the first place, to have their councils, which were accordingly assigned them, and were respectively composed of six councillors. The councillors of Ahura-mazda--called Amesha Spentas, or “Immortal Saints,” afterwards corrupted into Amshashpands--wore Vohu-mano (Bahman), Asha-va-hista (Ardibehesht), Khshathra-vairya (Shahravar), Qpenta-Armaiti (Isfand-armat), Haurvatat (Khordad), and Ameretat (Amerdat). Those of Angro-mainyus were Ako-mano, Indra, Qaurva, Naonhaitya, and two others whose names are interpreted as “Darkness” and “Poison.”