Passage 5.8.2
Πέλοψ δὲ ὕστερον γενεᾷ μάλιστα μετὰ Ἐνδυμίωνα τὸν ἀγῶνα τῷ Ὀλυμπίῳ Διὶ ἐποίησεν ἀξιολογώτατα ἀνθρώπων τῶν πρὸ αὐτοῦ. Πέλοπος δὲ τῶν παίδων σκεδασθέντων ἐξ Ἤλιδος ἀνὰ πᾶσαν τὴν ἄλλην Πελοπόννησον, Ἀμυθάων ὁ Κρηθέως Ἐνδυμίωνι ἀνεψιὸς πρὸς πατρός---εἶναι γάρ φασι καὶ Ἀέθλιον Αἰόλου, Διὸς δὲ ἐπίκλησιν---, ἔθηκεν ὁ Ἀμυθάων τὰ Ὀλύμπια, μετὰ δὲ αὐτὸν Πελίας τε καὶ Νηλεὺς ἐν κοινῷ.
After Endymion, it was Pelops who later established the contest for Olympian Zeus in a manner most distinguished among all who preceded him. When the sons of Pelops became scattered from Elis throughout the rest of the Peloponnese, Amythaon, son of Cretheus and cousin to Endymion on his father's side—for they say that Aethlius too was a son of Aeolus, though called a son of Zeus—Amythaon established the Olympic games, and after him Pelias and Neleus jointly maintained them.