History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
But finally these and the other Thebans who survived and were wandering up and down the city came to an agreement with the Plataeans to surrender themselves and their arms, to be dealt with in any way the Plataeans wished.
The Thebans in Plataea had fared thus;
but the main body of the Thebans, who were to have come in full force while it was still night, on the chance that things might not go well with those who had entered the city, received while on the way news of what had happened and were now hastening to the rescue.