History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
At Thuria they found that the faction opposed to the Athenians had recently been expelled in a revolution;
and as they were desirous, after collecting their whole armament at that place, to hold a review of it, on the chance that anyone had been left behind, and also to persuade the Thurians both to take part with them in the expedition with all zeal and, in view of the Athenians' present good fortune, to regard the same persons foes and friends as the Athenians did, they waited at Thuria and dealt with these matters.
About this same time the Peloponnesians in the twenty-five ships which lay facing the Athenian fleet at Naupactus in order to cover the passage of the merchant-ships to Sicily, having made preparations for a fight and having manned some additional ships, so that theirs were now but a little fewer than the Athenian ships, anchored off Erineus[*](A small place east of Rhium.) in Achaea in the district of Rhypae.
The place where they were anchored was crescent-shaped, and the land army, consisting of the Corinthians and the allies from the neighbourhood, having come to their support, was drawn up on either side of them on the projecting headlands, while the ships held the intervening space blocking the entrance; and the commander of the fleet was Polyanthes, a Corinthian.
Against these the Athenians sailed out from Naupactus with thirty-three ships under the command of Diphilus.[*](He seems to have brought a reinforcement of fifteen ships and to have superseded Conon (cf. 7.31.4).)
At first the Corinthians kept quiet; then the signal was raised, when the moment seemed favourable, and advancing against the Athenians they engaged them. And for a long time they withstood one another. Three ships of the Corinthians were destroyed;