Ahura Mazda
While there is no general consensus in scholarship whether Darius and his predecessors had been influenced by Zoroastrianism, it is well established that Darius was a firm believer in Ahura Mazda, whom he saw as the supreme deity. However, Ahura Mazda was also worshipped by adherents of the (Indo-)Iranian religious tradition. As can be seen at the Behistun Inscription, Darius believed that Ahura Mazda had appointed him to rule the Achaemenid Empire.