Passage 5.10.7
πρὸς αὐτῷ δὲ κατάκειται τῷ πέρατι Κλάδεος· ἔχει δὲ καὶ ἐς τὰ ἄλλα παρʼ Ἠλείων τιμὰς ποταμῶν μάλιστα μετά γε Ἀλφειόν. τὰ δὲ ἐς ἀριστερὰ ἀπὸ τοῦ Διὸς ὁ Πέλοψ καὶ Ἱπποδάμεια καὶ ὅ τε ἡνίοχός ἐστι τοῦ Πέλοπος καὶ ἵπποι δύο τε ἄνδρες, ἱπποκόμοι δὴ καὶ οὗτοι τῷ Πέλοπι. καὶ αὖθις ὁ ἀετὸς κάτεισιν ἐς στενόν, καὶ κατὰ τοῦτο Ἀλφειὸς ἐπʼ αὐτοῦ πεποίηται. τῷ δὲ ἀνδρὶ ὃς ἡνιοχεῖ τῷ Πέλοπι λόγῳ μὲν τῷ Τροιζηνίων ἐστὶν ὄνομα Σφαῖρος, ὁ δὲ ἐξηγητὴς ἔφασκεν ὁ ἐν Ὀλυμπίᾳ Κίλλαν εἶναι.
Near this boundary flows the Cladeus river, which is honored by the Eleans above all other rivers, except the Alpheus. To the left of the image of Zeus stand Pelops and Hippodameia, along with Pelops' charioteer, two horses, and two men who serve as Pelops' grooms. At this point, the vaulted roof narrows again, and above this narrow part an eagle sits, while below the eagle the river Alpheus is depicted. Regarding the man who drives the chariot for Pelops, according to the tradition of the Troezenians, his name is Sphairos; but the guide at Olympia stated that his name was Killas.