Ageladas' fame is enhanced by his having been the instructor of the three great masters, Phidias, Myron, and Polykleitos. The determination of the period when Ageladas flourished has given rise to a great deal of discussion, owing to the apparently contradictory statements in the writers who mention the name. Pausanias tells us that Ageladas cast a statue of Cleosthenes (who gained a victory in the chariot-race in the 66th Olympiad) with the chariot, horses, and charioteer, which was set up at Olympia. There were also at Olympia statues by him of Timasitheus of Delphi and Anochus of Tarentum. Timasitheus was put to death by the Athenians, for his participation in the attempt of Isagoras in Olympiad lxviii. 2 (507 BC); and Anochus (as we learn from Eusebius) was a victor in the games of the 65th Olympiad. So far everything is clear; and if we suppose Ageladas to have been born about 540 BC, he may very well have been the instructor of Phidias. On the other hand Pliny says that Ageladas, with Polykleitos, Phradmon, and Myron, flourished in the 87th Olympiad. This agrees with the statement of the scholiast on Aristophanes, that at Melite there was a statue of Heracles (Ἡρακλῆς ἀλεξίκακος), the work of Ageladas the Argive, which was set up during the great pestilence (Olympiad lxxxvii. 3. 4).
To these authorities must be added a passage of Pausanias, where he speaks of a statue of Zeus made by Ageladas for the Messenians of Naupactus. This must have been after the year 455 BC, when the Messenians were allowed by the Athenians to settle at Naupactus. In order to reconcile these conflicting statements, some suppose that Pliny's date is wrong, and that the statue of Heracles had been made by Ageladas long before it was set up at Melite. Others think that Pliny's date is correct, but that Ageladas did not make the statues of the Olympic victors mentioned by Pausanias until many years after their victories; which in the case of three persons, the dates of whose victories are so nearly the same, would be a very extraordinary coincidence.
The most probable solution of the difficulty is that of Friedrich Thiersch, who thinks that there were two artists of this name; one an Argive, the instructor of Phidias, born about 540 BC, the other a native of Sicyon, who flourished at the date assigned by Pliny, and was confounded by the scholiast on Aristophanes with his more illustrious namesake of Argos. Thiersch supports this hypothesis by an able criticism on a passage of Pausanias. Other scholars assume that there were two artists of the name of Ageladas, but both were Argives. Ageladas the Argive executed one of a group of three Muses, representing respectively the presiding geniuses of the diatonic, chromatic and enharmonic styles of Greek music. Canachus and Aristocles of Sicyon made the other two.