AGATHON (c. 448–400 B.c.)  , Athenian tragic poet, friend of Euripides and Plato, best known from his mention by Aristophanes (Thesmophoriazusae) and in Plato's Symposium, which describes the lfanquet given to celebrate his obtaining a prize for a tragedy (416) . He probably died at the court of Archelaus, king of Macedonia . He introduced certain innovations, and Aristotle (Poetica, 9) tells us that the plot of his AVOos was original, not, as usually, borrowed from mythological subjects . See Aristophanes, Thesmoph . 59, Io6, Eccles. too; Plato, Symp . 198 c; Plutarch, Symp . 3; Aelian, Var . Hist. xiv . 13; Ritsch, Opuscula, i . ; fragments in Nauck, Tragicorum Graecorum Fragmenta .