(Εὔφαντος), of Olynthus, a Pythagorean philosopher and tragic poet, who lived a little later than the period of the tragic Pleiad. He was the disciple of Eubulides of Miletus, and the instructor of Antigonus I. king of Macedonia. He wrote many tragedies, which were well received at the games. He also wrote a very highly esteemed work, περὶ Βασιλείας, addressed to Antigonus, and a history of his own times : he lived to a great age. (D. L. 2.110, 141.) The Euphantus whose history is quoted by Athenaeus (vi. p. 251d.) must have been a different person, since he mentioned Ptolemy III. of Egypt. (Vossius, de Hist. Graec. p. 69, ed. Westermann; Welcker, die Griech. Tragoed. p. 1268.)