Hystaspes (Old Persian: 𐎻𐏁𐎫𐎠𐎿𐎱 Vištāspa; Ancient Greek: Ὑστάσπης Hustáspēs) or Guštāsp (Persian: گشتاسپ Guštāsp) (fl. 550 BC), was a Persian satrap of Bactria and Persis. He was the father of Darius I, king of the Achaemenid Empire, and Artabanus, who was a trusted advisor to both his brother Darius as well as Darius's son and successor, Xerxes I.