The great contemporary scholar of religion Jonathan Z. Smith once remarked that the omnipresent substructure of human thought lies in the human capacity to make comparisons. In ancient Sumer, scribes crafted intricate similes. In classical Greece philosophers discussed and employed the critical tools of analogy and metaphor. And following the European Enlightenment, university professors made their contribution by inventing the field we know today as "comparative religion." From the field's earliest days, Zoroastrianism—the ancient dualistic religion of Iran, whose adherents worshiped Ahura Mazda ("Lord Wisdom") and his heavenly hosts and battled the evil Angra Mainyu ("Foul Spirit") and his demonic minions—has played a central role in the way the modern academy has studied the religions of the world.