Delian League
Writing between 431 and 411 BC, Thucydides credited Korkyra's conflict with Corinth over their joint city Epidamnus as a significant cause of the Peloponnesian War. Korkyra, otherwise neutral as far as the two major powers, the Delian League and the Peloponnesian League, were concerned, appealed to Athens, head of the Delian League, for assistance against Corinth, who belonged to the Peloponnesian League.