They even believed themselves directly commanded by that god to destroy other nations, who had incurred his very human hatred by not knowing of his authority. Moreover, they recognized the life of the soul of man and its continued spiritual existence in worlds of good or evil after death. Their religion, at least in its earlier stages, involved a view of life equal in nobility to that of many a modern philosopher. The creator Ahura-Mazda, whom the later Persians identified with Mithra, the sun god, had two sons, light and darkness, good and evil, Ormuzd and Ahriman. These two were always in struggle for dominion over the universe, and in their tremendous warfare they called to their banners every living thing and every force on earth.
Man holds a leading part in the great strife.
Every one by his own will ranges himself upon one side or the other, for he helps the cause of Ormuzd by every generous act and thought, advances that of Ahriman by every deed of shame. This truly noble philosophy of man's moral freedom and responsibility took definite form under the teaching of the sage, Zarathushtra, or, as the Greeks called him, Zoroaster. We can not trace the Aryan races to anything like the antiquity of the Semites. Assyrian and Babylonian records speak of these invaders vaguely as Scyths, or as the Manda or Kimmerians. We only really know that hordes of fierce, fighting nations began to press upon the Semitic civilization from the north, from the great plains of Russia, and of central Asia.