History of the Peloponnesian War

Having thus effected a union at day-break, they sat down at the place called Metropolis, and formed their encampment. Not long after, the Athenians came with their twenty ships into the Ambracian Gulf to assist the Argives; and Demosthenes arrived with two hundred heavy-armed of the Messenians, and sixty Athenian archers. The fleet therefore at Olpae blockaded the hill from the sea;

while the Acarnanians and a few of the Amphilochians (for the majority were forcibly detained by the Ambraciots) had by this time met at Argos, and were preparing to engage with the enemy, having appointed Demosthenes as commander of the whole army in concert with their own generals. He, having led them near to Olpae, encamped there;

a great ravine separating their armies. For five days they remained still, but on the sixth both sides drew up for battle. And as the force of the Peleponnesians was the larger, and outflanked his, Demosthenes, fearing that he might be surrounded, placed in ambush in a hollow way covered with a thicket, a body of heavy and light-armed troops, four hundred in all, that on the flank of the enemy which reached beyond his own, these troops might rise up in the very midst of the conflict and take them in their rear.

When the preparations were completed on both sides, they closed in battle. Demosthenes occupied the right wing with the Messenians and the few Athenians; while the remainder of the line was formed by the Acarnanians in their several divisions, and the Amphilochian dartmen that were present. The Peloponnesians and Ambraciots were drawn up without distinction, excepting the Mantineans, who kept together more on the left, though not in the extremity of the flank, for the extreme left was held by Eurylochus and his men, opposed to the Messenians and Demosthenes.

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.

The next day Menedaeus, who on the death of Eurylochus and Macarius had succeeded to the sole command, was at a loss, since so great a defeat had been experienced, to see in what way he should either remain and sustain a siege—cut off as he was by land, and at the same time, through the presence of the Athenian fleet, by sea—or should escape if he retreated.