Cleon (ca. 475-422 B.C.) was an aggressive Athenian political leader. He was the first member of the nonaristocratic classes to reach a prominent position in Athens's political structure.

From humble origins, Cleon rose to prominence by attacking the Athenian strong man Pericles and endeavored to succeed him after 429. Exploiting the reaction against Pericles and the angry mood of the people during the Peloponnesian War with Sparta, Cleon advocated in 427 the execution of every adult male and enslavement of the rest of the population of Mytilene. A nominally free ally of Athens, the city had joined Sparta and had then been forced to capitulate to Athens. Cleon's policy was adopted at first but defeated by a small majority upon reconsideration. The news reached Mytilene just in time to stop the executions. Cleon's proposal to execute the ringleaders--more than 1,000 according to the text of Thucydides--was carried out.

Thus Cleon...