The son of Arsames, Hystaspes was a member of the Persian royal house of the Achaemenids. He was satrap of Persis under Cambyses II, and probably under his second cousin Cyrus the Great also. He accompanied Cyrus on his expedition against the Massagetae. However, he was sent back to Persis to keep watch over his eldest son, Darius, whom Cyrus, after a dream, suspected of considering treason.
"Hystaspes, a very wise monarch, the father of Darius. Who while boldly penetrating into the remoter districts of upper India, came to a certain woody retreat, of which with its tranquil silence the Brahmans, men of sublime genius, were the possessors. From their teaching he learnt the principles of the motion of the world and of the stars, and the pure rites of sacrifice, as far as he could; and of what he learnt he infused some portion into the minds of the Magi, which they have handed down by tradition to later ages, each instructing his own children, and adding to it their own system of divination".
In ancient sources, Hystaspes is sometimes considered as identical with Vishtaspa (the Avestan name for Hystapes), an early patron of Zoroaster.[8]
The name of Hystaspes occurs in the inscriptions at Persepolis and in the Behistun Inscription, where the full lineage of Darius the Great is given:[10]
King Darius says: My father is Hystaspes; the father of Hystaspes was Arsames; the father of Arsames was Ariaramnes; the father of Ariaramnes was Teispes; the father of Teispes was Achaemenes.
King Darius says: That is why we are called Achaemenids; from antiquity we have been noble; from antiquity has our dynasty been royal.
King Darius says: Eight of my dynasty were kings before me; I am the ninth. Nine in succession we have been kings.
King Darius says: By the grace of Ahuramazda am I king; Ahuramazda has granted me the kingdom.
Hystaspes died in c. 499 and was buried in Persepolis, with a funerary cult subsequently being established in his name. Historian Lloyd Llewellyn-Jones suggests that the Takht-e Gohar, previously attributed as the tomb of Cambyses II, was actually that of Hystaspes.[11]