History of the Peloponnesian War

When the Peloponnesians, being now engaged, outflanked their opponents, and were surrounding their right, the Acarnanians, rising from the ambuscade, fell on them in the rear, and broke them; so that they did not stand to make any resistance, and, moreover, by their panic threw their main army into flight: for when they saw the division of Eurylochus, and the bravest of their forces being cut to pieces, they were far more alarmed. It was the Messenians, posted in that part of the field with Demosthenes, that performed the chief part of the work.

But the Ambraciots and those in the right wing defeated the division opposed to them, and pursued it back to Argos; for they are the most warlike of all in those parts.

When, however, on their return they saw their main army defeated, and the rest of the Acarnanians were pressing them closely, they escaped with difficulty into Olpe; and many of them were killed, while they hurried on without any order, excepting the Mantineans, who kept their ranks best of all the army during the retreat. And so the battle ended, after lasting till evening.