 Herodotus has no room for Cyaxares II in the "Histories", because his narrative has Cyrus leading a successful rebellion against his maternal grandfather, Astyages king of the Medes.As a consequence, the Medes became "slaves" of the Persians (1.129,130).Herodotus states that Astyages had no male heir (1.109); this may be compared to Xenophon's statement ("Cyropaedia" 8.5.19) that it was Cyaxares (II), son of Astyages, who had no male heir.