Zarathustra or Zarthost is also referred to by the name Zoroaster in western texts. He was believed to have lived during 600 B.C. in Persia, which is the region covered by modern-day Iran and Iraq. Current estimates have revised this date to anywhere between 1500 B.C. and 1000 B.C., or even earlier. This makes Zoroastrianism one of the oldest monotheist world religions.   Information About Zoroastrianism