History of the Peloponnesian War

Meanwhile the Potidaeans and the Peloponnesians with Aristeus were encamped on the side looking towards Olynthus on the isthmus, in expectation of the Athenians, and had established their market outside the city.

The allies had chosen Aristeus general of all the infantry; while the command of the cavalry was given to Perdiccas, who had at once left the alliance of the Athenians and gone back to that of the Potidaeans, having deputed Iolaus as his general.

The plan of Aristeus was to keep his own force on the isthmus, and await the attack of the Athenians; leaving the Chalcidians and the allies outside the isthmus, and the two hundred cavalry from Perdiccas in Olynthus to act upon the Athenian rear, on the occasion of their advancing against him; and thus to place the enemy between two fires.