To Zoroaster--the ancient sage of Iran--must always be assigned the first place in the intellectual history of Iranian Aryans who, wearied of constant roaming, settled down to an agricultural life at a time when the Vedic Hymns were still being composed in the plains of Central Asia. This new mode of life and the consequent stability of the institution of property among the settlers, made them hated by other Aryan tribes who had not yet shaken off their original nomadic habits, and occasionally plundered their more civilised kinsmen. Thus grew up the conflict between the two modes of life which found its earliest expression in the denunciation of the deities of each other--the Devas and the Ahuras. It was really the beginning of a long individualising process which gradually severed the Iranian branch from other Aryan tribes, and finally manifested itself in the religious system of Zoroaster[2:1]--the great prophet of Iran who lived and taught in the age of Solon and Thales. In the dim light of modern oriental research we see ancient Iranians divided between two camps--partisans of the powers of good, and partisans of the powers of evil--when the great sage joins their furious contest, and with his moral enthusiasm stamps out once for all the worship of demons as well as the intolerable ritual of the Magian priesthood. [2:1] Some European Scholars have held Zoroaster to be nothing more than a mythical personage. But since the publication of Professor Jackson's admirable Life of Zoroaster, the Iranian Prophet has, I believe, finally got out of the ordeal of modern criticism. It is, however, beside our purpose to trace the origin and growth of Zoroaster's religious system. Our object, in so far as the present investigation is concerned, is to glance at the metaphysical side of his revelation. We, therefore, wish to fix our attention on the sacred trinity of philosophy--God, Man and Nature.