Passage 5.9.5
πέμπτῃ δὲ Ὀλυμπιάδι καὶ ἐνενηκοστῇ ἐννέα ἑλλανοδίκας κατέστησαν· τρισὶ μὲν δὴ ἐπετέτραπτο ἐξ αὐτῶν ὁ δρόμος τῶν ἵππων, τοσούτοις δὲ ἑτέροις ἐπόπταις εἶναι τοῦ πεντάθλου, τοῖς δὲ ὑπολειπομένοις τὰ λοιπὰ ἔμελε τῶν ἀγωνισμάτων. δευτέρᾳ δὲ ἀπὸ ταύτης Ὀλυμπιάδι προσετέθη καὶ ὁ δέκατος ἀθλοθέτης. ἐπὶ δὲ τῆς τρίτης καὶ ἑκατοστῆς φυλαί τε Ἠλείοις δώδεκα καὶ εἷς ἀπὸ φυλῆς ἑκάστης ἐγένετο Ἑλλανοδίκης.
In the ninety-fifth Olympiad they appointed nine judges; three of these were put in charge of the horse-race, an equal number were appointed overseers of the pentathlon, and the remaining three supervised the rest of the contests. In the second Olympiad after this, a tenth judge was added. In the hundred and third Olympiad, when the Eleans had twelve tribes, one judge was chosen from each tribe, making twelve in all.