the dualistic religion founded by the Persian prophet Zoroaster in the late 7th or early 6th centuries bc and set forth in the sacred writings of the Zend-Avesta. It is based on the concept of a continuous struggle between Ormazd (or Ahura Mazda), the god of creation, light, and goodness, and his arch enemy, Ahriman, the spirit of evil and darkness, and it includes a highly developed ethical code