A major aspect of Zoroastrianism is how they discredited existing Iranian deities, and reused them in an expanded pantheon of gods subordinated to Ahura Mazdā. Their most difficult task was to find ways to reintegrate Apam Napāt (Apam Naphāt?), a deity who was perceived as the main rival to Ahura Mazdā, and the one who was initially branded as daeva. The subtle ways by which they achieved this is a testimony to their mastery in the art of sophistry, at a level seldom seen in the history of religions.