Greek professional speech writer, whose unpretentious simplicity became the model for a plain style of Attic Greek.

Lysias was the son of Cephalus, a wealthy native of Syracuse who settled in Athens. Plato, at the opening of the Republic, had drawn a charming picture of Cephalus and his sons Lysias and Polemarchus. After studying rhetoric in Italy, Lysias returned to Athens in 412. It was possibly then that he taught rhetoric. In 404, during the reign of the Thirty Tyrants, he and his brother Polemarchus were seized as aliens. Polemarchus was killed, but Lysias escaped to Megara, where he helped the cause of exiled Athenian democrats. On the restoration of Athenian democracy in 403, he returned to Athens and began writing speeches for litigants.

Of the more than 200 speeches attributed to Lysias in antiquity, only 35 survive. Some of these are incomplete, and some are not by Lysias. There also exist fragments of speeches quoted by later authors. A speech on Eros, or love, is found in the Phaedrus of Plato, although some scholars consider it an imitation or parody of Lysias, written by Plato. Lysias's surviving forensic speeches often deal with crimes against the state—murder, malicious wounding, sacrilege, and taking bribes. Lysias displays a characteristic adaptability in suiting his composition to the character of the speaker; and, though the tone of his professional writing was quiet, he was capable of passionate oratory, as exemplified in his own longest and most famous speech, “Against Eratosthenes,” denouncing one of the Thirty Tyrants for his part in the reign of terror that followed the collapse of Athens in 404. Another of his orations (“Agoratus”) is the best source for Athenian laws on adultery.