History of the Peloponnesian War

The same winter the Plataeans, who were still being besieged by the Peloponnesians and Boeotians, distressed by the failure of their provisions, and seeing no hope of relief from Athens, nor any other means of safety, formed a scheme with the Athenians besieged with them for escaping, if possible, by forcing their way over the enemy's walls; the attempt having been suggested by Theaenetus, son of Tolmides, a soothsayer, and Eupompides, son of Daimachus, one of their generals. At first all were to join:

afterwards, half hung back, thinking the risk great; about two hundred and twenty, however, voluntarily persevered in the attempt, which was carried out in the following way.