History of the Peloponnesian War

When they were in fight, and that the Peloponnesians with that wing overreached and had encircled the right wing of their enemies, those Acarnanians that lay in ambush, coming in at their backs, charged them and put them to flight in such sort as they endured not the first brunt, and besides, caused the greatest part of the army through affright to run away. For when they saw that part of it defeated which was with Eurylochus, which was the best of their army, they were a great deal the more afraid. And the Messenians that were in that part of the army with Demosthenes, pursuing them, dispatched the greatest part of the execution.

But the Ambraciotes that were in the right wing, on that part had the victory, and chased the enemy unto the city of Argos.

But in their retreat, when they saw that the greatest part of the army was vanquished, the rest of the Acarnanians setting upon them, they had much ado to recover Olpae in safety. And many of them were slain, whilst they ran into it out of array and in disorder, save only the Mantineans, for these made a more orderly retreat than any part of the army. And so this battle ended, having lasted till the evening.

The next day, Menedaius (Eurylochus and Macarius being now slain), taking the command upon him and not finding how, if he stayed, he should be able to sustain a siege, wherein he should both be shut up by land and also with those Attic galleys by sea, or if he should depart, how he might do it safely, had speech with Demosthenes and the Acarnanian captains, both about a truce for his departure and for the receiving of the bodies of the slain.