History of the Peloponnesian War

And the friends of the exiles, noticing the murmuring of the people, all began more openly than before to urge that this proposal be adopted.

But the leaders of the popular party, realizing that the populace under the pressure of their distress would not be able to hold out with them, became frightened and made overtures to the Athenian generals, Hippocrates son of Ariphron and Demosthenes son of Alcisthenes, proposing to surrender the city to them; for they thought that this course would be less dangerous to themselves than the restoration of the citizens whom they had banished. They agreed, in the first place, that the Athenians should take possession of the long walls (the distance between the city and the harbour at Nisaea was about eight stadia), in order to prevent the Peloponnesians from sending reinforcements from Nisaea, where they formed the sole garrison to keep their hold on Megara, and, in the second place, that they would do their best to hand over to them the upper-town as well, believing that, as soon as this was done, their fellow-citizens would more readily go over to the Athenian side.

So, then, as soon as due preparations, both in word and act, had been made by both parties, the Athenians sailed under cover of night to Minoa, the island which lies off Megara, taking six hundred hoplites under the command of Hippocrates, and took cover in a ditch, not far from the town, where bricks had been made for the walls.

A second company consisting of light-armed Plataeans and frontier-patrols under the command of the other general, Demosthenes, set an ambuscade at Enyalius, which is somewhat nearer. And all that night no one perceived what was going on except the men whose business it was to know.