History of the Peloponnesian War

During this winter, after the fleet of the Peloponnesians had dispersed, the Athenians at Naupactus under the command of Phormio, after coasting along to Astacus, and there disembarking, marched into the interior of Acarnania, with four hundred heavy-armed of the Athenians from the ships and four hundred of the Messenians. From Stratus, Coronta, and some other places, they expelled certain individuals who were not thought to be true to them; and having restored Cynes son of Theolytus to Coronta, returned again to their vessels.

For against the Aeniadae, who alone of the Acarnanians had always been hostile to them, they did not think it possible to march during the winter, as the river Achelous, which flows from Mount Pindus through Dolopia and the country of the Agraeans and Amphilochians and the plain of Acarnania, passing by the town of Stratus in the upper part of its course, and by Aeniadae near its mouth, forms lakes round their city, and so makes it impracticable to lead an army against it in the winter on account of the water.