Thrasymachus (fl. 427 B.C.), Greek Sophist from Bithynia who is known mainly as a character in Book I of Plato’s Republic. He traveled and taught extensively throughout the Greek world, and was well known in Athens as a teacher and as the author of treatises on rhetoric. Innovative in his style, he was credited with inventing the ‘middle style’ of rhetoric. The only surviving fragment of a speech by Thrasymachus was written for delivery by an Athenian citizen in the assembly, at a time when Athens was not faring well in the Peloponnesian War; it shows him concerned with the efficiency of government, pleading with the Athenians to recognize their common interests and give up their factionalism. Our only other source for his views on political matters is Plato’s Republic, which most scholars accept as presenting at least a half-truth about Thrasymachus. There, Thrasymachus is represented as a foil to Socrates, claiming that justice is only what benefits the stronger, i.e., the rulers. From the point of view of those who are ruled, then, justice always serves the interest of someone else, and rulers who seek their own advantage are unjust. See also SOPHIST. P.Wo.