History of the Peloponnesian War

And when they were at the isthmus, and saw the enemy preparing for battle, they also took an opposite position; and not long after they began the engagement.

And just the wing of Aristeus, and such picked troops of the Corinthians and the rest as were around him, routed the wing opposed to them, and advanced in pursuit a considerable distance; but the remaining force of the Potidaeans and Peloponnesians was beaten by the Athenians, and fled within the wall for refuge.

When Aristeus was returning from the pursuit, seeing the rest of the army conquered, he was at a loss which place he should risk going to, whether towards Olynthus, or to Potidaea. He determined, however, to draw his men into as small a space as possible, and at a running pace force his way into Potidaea: and he passed along the breakwater through the sea, annoyed by missiles [from the Athenian slips], and with difficulty; having lost a few men, but saved the rest.

Now the auxiliaries of the Potidaeans from Olynthus, (the town is about sixty stades off, and within sight,) when the battle was beginning, and the signals had been hoisted, advanced a short distance to give succour, and the Macedonian horse drew up against them to prevent it; but when the victory soon declared for the Athenians, and the signals had been taken down, they retired again within the wall, and the Macedonians to the Athenians. So neither side had any cavalry present [in the engagement].