Ancient Iranian religion, the creation of which is attributed to the mythical prophet Zarathustra (Zoroaster). Zoroastrianism was formed by the 7th century B.C. Zoroastrianism is based on the doctrine of a permanent struggle in the world between two opposite principles: goodness embodied by the light deity Ahuramazda, and evil embodied by the dark deity Ahriman. He had a great influence on Judaism and Christianity.