The Zoroastrians marked Sadeh, an ancient feast celebrating the creation of fire, in Tehran, Iran this week. Sadeh has been observed since the days when Zoroastrianism was the dominant religion in the powerful Persian empire. Zoroastrianism is the religion and philosophy based on the teachings ascribed to the prophet Zoroaster, after whom the religion is named. The term Zoroastrianism is in general usage, essentially synonymous with Mazdaism, i.e. the worship of Ahura Mazda, exalted by Zoroaster as the supreme divine authority.