History of the Peloponnesian War

Then each of the Athenians, as he successively entered, proceeded against the wall.

And of the Peloponnesian garrison a few at first resisted, and defended themselves, and some of them were killed; but the greater part took to flight, being terrified in consequence of the enemy having attacked them by night, and the Megarean traitors fighting against them; and thinking that all the Megareans had betrayed them.

For it happened that the Athenian herald had of his own accord proclaimed, that whoever of the Megareans wished, should go and pile his arms with the Athenians. So when they heard that, they stayed no longer; but thinking that they were certainly the objects of a common attack, fled for refuge to Nisaea.

In the morning, when the walls were now taken, and the Megareans in the city were in confusion, those who had negotiated with the Athenians, and others with them, viz. the popular party who were privy to the measure, said that they ought to throw open the gates, and march out to battle. It had been arranged by them, that when the gates were opened, the Athenians should rush in;

and they themselves would be distinguished from the rest, for they said they would anoint themselves with oil, that they might not be hurt. And they felt the greater security in opening the gates, since, according to agreement, the four thousand Athenian heavy-armed from Eleusis, and six hundred horse, had marched all night, and were now there.

But when they were anointed, and were now standing about the gates, one of their associates gave information of the plot to the other party, who consequently united, and came in a body, and urged that they ought neither to march out, (for not even before, when they were stronger, had they ever ventured on this,) nor to bring the city into evident danger; and if any one did not obey them, there, [in Megara itself,] should the battle be fought. But they gave no intimation of their being acquainted with their practices, but positively maintained that they were giving the best advice; and at the same time they kept their post about the gates, so that it was not possible for the conspirators to accomplish what they intended.