History of the Peloponnesian War

This is the Theban account of the matter, and they say that they had an oath given them. The Plataeans, on the other hand, do not admit any promise of an immediate surrender, but make it contingent upon subsequent negotiation: the oath they deny altogether.

Be this as it may, upon the Thebans retiring from their territory without committing any injury, the Plataeans hastily got in whatever they had in the country and immediately put the men to death. The prisoners were a hundred and eighty in number; Eurymachus, the person with whom the traitors had negotiated, being one.

This done, the Plataeans sent a messenger to Athens, gave back the dead to the Thebans under a truce, and arranged things in the city as seemed best to meet the present emergency.