(also Zoroaster, Zarthosht)
Zarathushtra was the founder of Zoroastrianism, and was estimated to have lived sometime in the second millenium BCE (although some who follow the religion claim that Zoroastrianism was founded around 6000 BCE.)
According to Zoroastrian legend, the birth of Zarathushtra was foretold and that some evil men tried to kill him as a child. Zarathushtra preached about monotheism in a world of polytheists. Gradually Zoroastrainism rose to gain favor of the state, becomming the official religion of Persia until 650 CE when Islam took over.