Plato, Laws 695b

αὑτοῦ τοὺς ὑεῖς, ὅθεν ἐγένοντο οἵους ἦν αὐτοὺς εἰκὸς γενέσθαι, τροφῇ ἀνεπιπλήκτῳ τραφέντας. παραλαβόντες δʼ οὖν οἱ παῖδες τελευτήσαντος Κύρου τρυφῆς μεστοὶ καὶ ἀνεπιπληξίας, πρῶτον μὲν τὸν ἕτερον ἅτερος ἀπέκτεινε τῷ ἴσῳ ἀγανακτῶν, μετὰ δὲ τοῦτο αὐτὸς μαινόμενος ὑπὸ μέθης τε καὶ ἀπαιδευσίας τὴν ἀρχὴν ἀπώλεσεν ὑπὸ Μήδων τε καὶ τοῦ λεγομένου τότε εὐνούχου, καταφρονήσαντος τῆς Καμβύσου μωρίας.

such as they were likely to become when reared with a rearing that spared the rod. So when, at the death of Cyrus, his sons took over the kingdom, over-pampered and undisciplined as they were, first, the one killed the other, through annoyance at his being put on an equality with himself, and presently, being mad with drink and debauchery, he lost his own throne at the hands of the Medes, under the man then called the Eunuch, who despised the stupidity of Cambyses. That, certainly, is the story, and probably it is near to