The Acarnanians, finding themselves invaded by a large army by land, and from the sea threatened by a hostile fleet, made no combined attempt at resistance, but remained to defend their homes, and sent for help to Phormio, who replied that, when a fleet was on the point of sailing from Corinth, it was impossible for him to leave Naupactus unprotected. The Peloponnesians meanwhile and their allies advanced upon Stratus in three divisions, with the intention of encamping near it and attempting the wall by force if they failed to succeed by negotiation. The order of march was as follows: the centre was occupied by the Chaonians and the rest of the barbarians, with the Leucadians and Anactorians and their followers on the right, and Cnemus with the Peloponnesians and Ambraciots on the left; each division being a long way off from, and sometimes even out of sight of, the others. The Hellenes advanced in good order, keeping a look-out till they encamped in a good position; but the Chaonians, filled with self-confidence, and having the highest character for courage among the tribes of that part of the continent, without waiting to occupy their camp, rushed on with the rest of the barbarians, in the idea that they should take the town by assault and obtain the sole glory of the enterprise. While they were coming on, the Stratians, becoming aware how things stood, and thinking that the defeat of this division would considerably dishearten the Hellenes behind it, occupied the environs of the town with ambuscades, and as soon as they approached engaged them at close quarters from the city and the ambuscades. A panic seizing the Chaonians, great numbers of them were slain; and as soon as they were seen to give way the rest of the barbarians turned and fled.
Owing to the distance by which their allies had preceded them, neither of the Hellenic divisions knew anything of the battle, but fancied they were hastening on to encamp. However, when the flying barbarians broke in upon them, they opened their ranks to receive them, brought their divisions together, and stopped quiet where they were for the day; the Stratians not offering to engage them, as the rest of the Acarnanians had not yet arrived, but contenting themselves with slinging at them from a distance, which distressed them greatly, as there was no stirring without their armour. The Acarnanians would seem to excel in this mode of warfare.
As soon as night fell, Cnemus hastily drew off his army to the river Anapus, about nine miles from Stratus, recovering his dead next day under truce, and being there joined by the friendly Oeniadae, fell back upon their city before the enemy's reinforcements came up. From hence each returned home; and the Stratians set up a trophy for the battle with the barbarians.
Meanwhile the fleet from Corinth and the rest of the confederates in the Crissaean Gulf, which was to have co-operated with Cnemus and prevented the coast Acarnanians from joining their countrymen in the interior, was disabled from doing so by being compelled about the same time as the battle at Stratus to fight with Phormio and the twenty Athenian vessels stationed at Naupactus. For they were watched, as they coasted along out of the gulf, by Phormio, who wished to attack in the open sea. But the Corinthians and allies had started for Acarnania without any idea of fighting at sea, and with vessels more like transports for carrying soldiers; besides which, they never dreamed of the twenty Athenian ships venturing to engage their forty-seven. However, while they were coasting along their own shore, there were the Athenians sailing along in line with them; and when they tried to cross over from Patrae in Achaea to the mainland on the other side, on their way to Acarnania, they saw them again coming out from Chalcis and the river Evenus to meet them. They slipped from their moorings in the night, but were observed, and were at length compelled to fight in mid passage. Each state that contributed to the armament had its own general; the Corinthian commanders were Machaon, Isocrates, and Agatharchidas. The Peloponnesians ranged their vessels in as large a circle as possible without leaving an opening, with the prows outside and the sterns in; and placed within all the small craft in company, and their five best sailers to issue out at a moment's notice and strengthen any point threatened by the enemy.