History of the Peloponnesian War

The same summer the people of the city of Megara, being harassed in the war by the Athenians, who regularly invaded their country in full force twice every year, and also by their own exiles in Pegae, who had been expelled in a revolution by the popular party and kept annoying them by raiding the country, began to say to one another that they ought to receive the fugitives back, so that the city should not be exposed to ruin from both directions at once.

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.