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Hystaspis(hĭstăs`pĭs), Old Persian Vishtaspa, fl. 6th cent. B.C., ruler of ancient Persia, father of Darius IDarius I
(Darius the Great) , d. 486 B.C., king of ancient Persia (521–486 B.C.), called also Dariavaush and Darius Hystaspis (after his father, Hystaspes or Vishtaspa).
..... Click the link for more information. . Under him Darius was governor of Parthia. The legendary patron of Zoroaster is also called Hystaspes or Vishtaspa; he may or may not be the same as Darius' father.