The Affair of Epidamnus, also known as the Epidamnian Affair, is cited by the Ancient Greek historian Thucydides as one of the major immediate causes for the Peloponnesian War. The conflict began as a minor coup by a democratic faction of the city-state of Epidamnus (later Roman Dyrrachium, now modern-day Durrës), but eventually escalated into a major conflict between the cities of Athens and Corcyra (modern Corfu) on one side and the city of Corinth on the other. The culminating Battle of Sybota subsequently led to the Potidaean Affair and the Megarian Decree, both also major contributors to the final outbreak of hostilities between Athens and Sparta, beginning the Peloponnesian War.