History of the Peloponnesian War

Arriving next at Mt. Thyamus, which belongs to the Agraeans, they went through the pass over it and came down into Argive territory after nightfall, whence they succeeded in passing unobserved between the city of Argos and the Acarnanian guard at Crenae, finally joining the Ambraciots at Olpae.

After the two armies had effected a junction, at daybreak they took post at a place called Metropolis and made camp. Not long afterwards the Athenians with their twenty ships arrived in the Ambracian Gulf, reinforcing the Argives; and Demosthenes also came with two hundred Messenian hoplites and sixty Athenian bowmen.

The ships lay at sea about the hill of Olpae, blockading it; but the Acarnanians and a few of the Amphilochians—for most of these were kept from moving by the Ambraciots—had already gathered at Argos and were preparing for battle with their opponents, having chosen Demosthenes to command the whole allied force in concert with their own generals. And he, leading them close to Olpae, encamped;

and a great ravine separated the two armies. For five days they kept quiet, but on the sixth both sides drew up in order of battle. Now the army of the Peloponnesians was larger than that of Demosthenes and outflanked it; he, therefore, fearing that he might be surrounded, stationed in a sunken road overgrown with buses an ambush of hoplites and light-troops, about four hundred all together, his purpose being that in the very moment of collision these troops should leap from their hiding-place and take the enemy in the rear at the point where his line overlapped.

When both sides were ready they came to close quarters. Demosthenes with the Messenians and a few Athenian troops had the right wing; the rest of the line was held by the Acarnanians, arrayed by tribes, and such Amphilochian javelin-men as were present. But the Peloponnesians and Ambraciots were mingled together, except the Mantineans; these were massed more on the left wing, though not at its extremity, for that position, which was opposite Demosthenes and the Messenians, was held by Eurylochus and the troops under him.

When finally the armies were at close quarters and the Peloponnesians outflanked with their left the right wing of their opponents and were about to encircle it, the Acarnanians, coming upon them from their ambush, fell upon their rear and routed them, so that they did not stand to make resistance and in their panic caused the greater part of their army to take to flight also; for when they saw the division under Eurylochus, their best troops, being cut to pieces, they were far more panic-stricken. And it was the Messenians, who were in this part of the field under the command of Demosthenes, that bore the brunt of the battle.