History of the Peloponnesian War

But the rival factions of Megara were afraid, the one that he might bring in the exiles and drive them out, the other that the populace, fearing this very thing, might attack them, and that the city, being at war with itself, while the Athenians were lying in wait near at hand, might be ruined. They, therefore, did not admit Brasidas, both parties thinking it best to wait and see what would happen.

For each party expected that there would be a battle between the Athenians and the relieving army, and so it was safer for them not to join the side which anyone favoured until it was victorious. So then Brasidas, when he could not persuade them, withdrew once more to his own army.

At daybreak the Boeotians arrived. They had intended, even before Brasidas summoned them, to go to the aid of Megara, feeling that the danger was not alien to them, and were already at Plataea with all their forces; but when the summons actually came, they were greatly strengthened in their purpose, and sent on two thousand two hundred hoplites and six hundred cavalry, returning home with the larger part of their army.

Then, finally, when their whole army was at hand, consisting of not less than six thousand hoplites, and the Athenian hoplites were in line about Nisaea and the sea, while the lightarmed troops were scattered up and down the plain, the Boeotian cavalry fell upon the latter and drove them to the sea. The attack was unexpected, for hitherto no reinforcements had ever come to the Megarians from any quarter.