Which god did the Persian King Darius 1st worship?

Persian King Darius I primarily worshipped Ahura Mazda, the supreme god of Zoroastrianism. He promoted this religion during his reign, emphasizing the importance of truth, order, and justice. Darius's inscriptions and monuments, particularly the Behistun Inscription, reflect his devotion to Ahura Mazda, portraying him as the divine source of his authority and success.