Clistiienes, an Athenian statesman, the grandson of a tyrant of Sicyon, of the same name, and the son of Megacles, and at the end of the rule of the Pisistratiche the head of the Alcmaoonidce, their chief enemies. When, with the assistance of the Delphic oracle and the Spartans, Hippias was banished from Athens (510 B. 0.), Clisthcnes, in order to secure his ascendancy over his rival Isagoras, chose the defence of the cause of the people, and succeeded, with the favor of the Pythia, in introducing some important changes in the ancient constitution of Athens; among others, the division of Attica into ten instead of four tribes, each consisting of several demi, under demarchs; the increase of the number of senators from 400 to 500, 50 from each tribe; and, as some say, the law of ostracism, so remarkable in the history of that state. Clisthcnes, being suspected of the desire of tyrannical power, was himself banished, but afterward returned, overcoming his enemies. He was grandfather to Pericles.