(Ἀστυάγης), king of Media, (called by Ctesias Ἀστυϊγᾶς, and by Diodorus Ἀσπάδας), was the son and successor of Cyaxares. The accounts of this king given by Herodotus, Ctesias, and Xenophon, differ in several important particulars. We learn from Herodotus (1.74), that in the compact made between Cyaxares and Alyattes in B. C. 610, it was agreed that Astyages should marry Aryenis, the daughter of Alyattes. According to the chronology of Herodotus, he succeeded his father in B. C. 595, and reigned 35 years. (1.130.) His government was harsh. (1.123.) Alarmed by a dream, he gave his daughter Mandane in marriage to Cambyses, a Persian of good family. (1.107.) Another dream induced him to send Harpagus to destroy the offspring of this marriage. The child, the future conqueror of the Medes, was given to a herdsman to expose, but he brought it up as his own. Years afterwards, circumstances occurred which brought the young Cyrus under the notice of Astyages, who, on inquiry, discovered his parentage. He inflicted a cruel punishment on Harpagus, who waited his time for revenge. When Cyrus had grown up to man's estate, Harpgus induced him to instigate the Persians to revolt, and, having been appointed general of the Median forces, he deserted with the greater part of them to Cyrus. Astyages was taken prisoner, and Cyrus mounted the throne. He treated the captive monarch with mildness, but kept him in confinement till his death.

Ctesias agrees with Herodotus in making Astyages the last king of the Medes, but says, that Cyrus was in no way related to him till he married his daughter Amytis. When Astyages was attacked by Cyrus, he fled to Ecbatana, and was concealed in the palace by Amytis and her husband Spitamas, but discovered himself to his pursuers, to prevent his daughter and her husband and children from being put to the torture to induce them to reveal where he was hidden. He was loaded with chains by Oebaras, but soon afterwards was liberated by Cyrus, who treated him with great respect, and made him governor of the Barcanii, a Parthian people on the borders of Hyrcania. Spitamas was subsequently put to death by the orders of Cyrus, who married Amytis. Some time after, Amytis and Cyrus being desirous of seeing Astyages, a eunuch named Petisaces was sent to escort him from his satrapy, but, at the instigation of Ocbaras, left him to perish in a desert region. The crime was revealed by means of a dream, and Amytis took a cruel revenge on Petisaces. The body of Astyages was found, and buried with all due honours. We are told that, in the course of his reign, Astyages had waged war with the Bactrians with doubtful success. (Ctes. apud Phot. Cod. 72. p. 36, ed. Bekker.)

Xenophon, like Herodotus, makes Cyrus the grandson of Astyages, but says, that Astyages was succeeded by his son Cyaxares II., on whose death Cyrus succeeded to the vacant throne. (Cyrop. i, 5.2.) This account seems to tally better with the notices contained in the book of Daniel. (5.31, 6.1, 9.1.) Dareius the Mede, mentioned there and by Josephus (10.11.4), is apparently the same with Cyaxares II. (Compare the account in the Cyropaedeia of the joint expedition of Cyaxares and Cyrus against the Assyrians.) In that case, Ahasuerus, the father of Dareius, will be identical with Astyages. The existence of Cyaxares II. seems also to be recognized by Aeschylus, Aesch. Pers. 766. But the question is by no means free from difficulty.