Supreme god of ancient Iranian religion, especially Zoroastrianism .
Ahura Mazda was worshiped by Darius I and his successors as the greatest god and the protector of the just king. Zoroaster taught that Ahura Mazda created the universe and maintains the cosmic order, and that the history of the world consists of the battle between two spirits he created
the beneficent Spenta Mainyu and the destructive Angra Mainyu. The Avesta identifies Ahura Mazda himself with the beneficent spirit and represents him as bountiful, all-knowing, and the creator of everything good. In late sources (from the 3rd century), Zurvan ("Time") is the father of the twins Ormazd (Ahura Mazda) and Ahriman (Angra Mainyu), who in orthodox Mazdaism (Zoroastrianism and Parsiism) reign alternately over the world until Ormazd's ultimate victory.