THE HISTORY OF THE PELOPONNESIAN WAR

Peloponnesian War , 431-404 BC, decisive struggle in ancient Greece between Athens and Sparta. It ruined Athens, at least for a time. The rivalry between Athens' maritime domain and Sparta's land empire was of long standing. Athens under Pericles (from 445 BC) had become a bastion of Greek democracy, with a foreign policy of regularly intervening to help local democrats. The Spartans, who favored oligarchies like their own, resented and feared the imperialism and cultural ascendancy of Athens.
The Peloponnesian War by Thucydides.