The monarch appears to have been required to send his eldest son as a sort of hostage to the Court of his superior, where he was held in a species of honorable captivity, not being allowed to quit the Court and return home without leave, but being otherwise well treated.

The fidelity of the father was probably supposed to be in this way secured while it might be hoped that the son would be conciliated, and made an attached and willing dependent.
When Persian history first fairly opens upon us in the pages of Xenophon and of Nicolaus Damascenus, this is the condition of things which we find existing.

Cambyses, the father of Cyrus the Great--called Atradates by the Syrian writer--is ruler of Persia, and resides in his native country, while his son Cyrus is permanently, or at any rate usually, resident at the Median Court, where he is in high favor with the reigning monarch, Astyages.

According to Xenophon, who has here the support of Herodotus, he is Astyages' grandson, his father, Cambyses, being married to Mandane, that monarch's daughter.

According to Nicolaus, who in this agrees with Ctesias, he is no way related to Astyages, who retains him at his court because he is personally attached to him.