Zoroastrianism is the ancient, pre-Islamic religion of Persia (modern-day Iran). It survives there in isolated areas but primarily exists in India, where the descendants of Zoroastrian Persian immigrants are known as Parsis, or Parsees. In India the religion is called Parsiism.
Founded by the Iranian prophet and reformer Zoroaster in the 6th century BCE, Zoroastrianism contains both monotheistic and dualistic features. Although a fairly small religion today, numbering about 200,000 adherents, it shares many central concepts with the major world religions of Judaism, Christianity, and Islam.