History of the Peloponnesian War

As the Epidamnians paid no heed to them the Corcyraeans proceeded against them with forty ships, accompanied by the exiles whom they intended to restore, and taking along the Illyrians also.

And sitting down before the city they proclaimed that the foreigners and any Epidamnians who wished might go away in safety; otherwise they would treat them as enemies. But when the Epidamnians would not comply, the Corcyraeans laid siege to the city, which is connected with the shore by an isthmus.