Zoroastrianism is a religion founded in ancient times by the prophet Zarathushtra, known to the Greeks as Zoroaster.

Zoroastrianism was the dominant world religion during the Persian empires (559 BC to 651 AC), and was thus the most powerful world religion at the time of Jesus. It had a major influence on other religions. It is still practiced world-wide, especially in Iran and India.

The last figure for the number of Zoroastrians was around 140,000. The largest populations are in India and Iran. J Hinnells' booklet Zoroastrianism and the Parsis (p.8) has 17,000 in Iran and 92,000 in India. North American Zoroastrians are reported to be around 5,000