Darius passed over his eldest son for Xerxes, grandson of Cyrus, on an argument supplied by an exiled Spartan king

Herodotus says Darius I had three sons by his first wife, a daughter of Gobryas, born before he became king; the eldest was Artobazanes. After he took the throne he had four sons by Atossa, daughter of Cyrus the Great; the eldest was Xerxes. Artobazanes claimed the throne as the eldest son, by a custom he said all men kept. Xerxes answered that his mother was the daughter of Cyrus. Demaratus, the exiled former king of Sparta, was at Susa and told Xerxes to argue that he was born after his father became king, as in Spartan custom. Darius accepted the argument and named Xerxes. Herodotus adds that Xerxes would have won anyway, because "Atossa was all-powerful." Xerxes's own inscription at Persepolis says: "Darius had other sons, but ... my father Darius made me the greatest after himself." Darius died in 486 BC. Britannica notes reliefs at Persepolis showing the heir standing behind the enthroned king. In 465 BC Xerxes and his eldest son were killed by members of his court, among them the minister Artabanus, and another son, Artaxerxes I, kept power. The inscription was found in the building at Persepolis called the harem, in four copies and a Babylonian translation.