For, cut off from the intellectual and imaginative sources of Greece and Rome, the state and statesmanship, legislation and law, society and manners, philosophy, religion, literature, art, and even artistic appreciation, run readily shallow and soon dry. […] According to the Theory of Improvement, or Progress, man, beginning with crude dreams and fancies about experience, life, the world, and God, has gradually developed truer and higher conceptions of his own nature, of his relation to the world about him, of duty, of art, and of religion. […] Zoroaster, a holy man of God, was the founder or the reformer of the Persian religion. […] , and his system became the dominant religion of Western Asia from the time of Cyrus (550 b.c. […] It is important to understand that the more ideal Olympian religion absorbed features of inferior religions, and that Jupiter, when represented as appropriating the characteristics of other gods, was sometimes, also, accredited with their wives.