History of the Peloponnesian War
Thucydides
Thucydides. History of the Peloponnesian War. Crawley, Richard, translator. London and Toronto: J. M. Dent and Sons Ltd.; New York: E. P. Dutton and Co., 1914.
Their stronghold having been taken by an attack, the garrison took refuge in a body upon some high ground and there capitulated, agreeing to give up their mercenary auxiliaries, lay down their arms, and commit themselves to the discretion of the Athenian people.
The generals carried them across under truce to the island of Ptychia, to be kept in custody until they could be sent to Athens, upon the understanding that if any were caught running away, all would lose the benefit of the treaty.
Meanwhile the leaders of the Corcyraean commons, afraid that the Athenians might spare the lives of the prisoners, had recourse to the following stratagem.
They gained over some few men on the island by secretly sending friends with instructions to provide them with a boat, and to tell them, as if for their own sakes, that they had best escape as quickly as possible, as the Athenian generals were going to give them up to the Corcyraean people.