Passage 4.3.8
γὰρ ἔτι ὄντα ἔτρεφεν αὐτὸν ὁ Κύψελος--- περιγίνεται μόνος τοῦ οἴκου, καὶ ὡς ἀνὴρ ἐγένετο, οἱ Ἀρκάδες κατάγουσιν αὐτὸν ἐς Μεσσήνην· συγκατήγαγον δὲ καὶ οἱ λοιποὶ βασιλεῖς τῶν Δωριέων, οἵ τε Ἀριστοδήμου παῖδες καὶ Ἴσθμιος ὁ Τημένου. Αἴπυτος δὲ ὡς ἐβασίλευσεν, ἐτιμωρήσατο μὲν τοῦ πατρὸς τοὺς φονέας, ἐτιμωρήσατο δὲ καὶ ὅσοι τοῦ φόνου παραίτιοι καθεστήκεσαν· προσαγόμενος δὲ τοὺς μὲν ἐν τέλει τῶν Μεσσηνίων θεραπείαις, ὅσοι δὲ ἦσαν τοῦ δήμου, δωρεαῖς, ἐς τοσοῦτο προέβη τιμῆς ὡς καὶ τοὺς ἀπογόνους Αἰπυτίδας ἀντὶ Ἡρακλειδῶν κληθῆναι.
For while he was yet alive, Cypselus brought him up. Being the only survivor of his household, when he had grown to manhood, the Arcadians restored him to Messene. The other kings of the Dorians helped in this restoration, including the sons of Aristodemus and Isthmius, son of Temenus. When Aepytus had become king, he avenged the murderers of his father, and also exacted vengeance upon all who had shared guilt in the crime. He then sought the favor of the leading men of the Messenians by honors, and of the common people by gifts, and raised himself in esteem to such a degree that his descendants were called Aepytidae instead of Heracleidae.