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.
The generals accordingly conveyed the men under truce to the island of Ptychia[*](cf. iii. lxxv. 5; now called Vido.) to be kept under custody there until they should be sent to Athens, and the understanding was that if anyone should be caught trying to run away the truce should be regarded as broken for them all.
But the leaders of the popular party at Corcyra were afraid that the Athenians would not put them to death on their arrival at Athens, and therefore resorted to the following stratagem.
They first tried to persuade a few of the men on the island to run away, by secretly sending thither friends who were instructed to say, with a show of good will, that the best course for them was to do this with no loss of time, and promising to have a boat ready; for the Athenian generals, they explained, were intending to deliver them up to the Corcyraean populace.
And when the men had been persuaded, and were caught sailing away in the boat which the others had provided. the truce was broken and the whole party was delivered up to the Corcyraeans.
But what chiefly contributed to such a result, so that the pretext seemed quite plausible and that those who devised the scheme felt little fear about putting it into effect, was the fact that the Athenian generals showed that they would not be willing, as they were bound for Sicily themselves, to have the men conveyed to Athens by others, who would thus get the credit for conducting them.
Now the Corcyraeans took over the prisoners and shut them up in a large building; afterwards they led them out in groups of twenty and marched them down between two lines of hoplites stationed on either side, the prisoners being bound to one another and receiving blows and stabs from the men who stood in the lines, if any of these perchance saw among them a personal enemy; and men with scourges walked by their sides to quicken the steps of such as proceeded too slowly on the way.