History of the Peloponnesian War

After the soldiers had grounded arms in the marketplace, those who had invited them in wished them to set to work at once and go to their enemies' houses. This, however, the Thebans refused to do, but determined to make a conciliatory proclamation, and if possible to come to a friendly understanding with the citizens. Their herald accordingly invited any who wished to resume their old place in the confederacy of their countrymen to ground arms with them, for they thought that in this way the city would readily join them.

On becoming aware of the presence of the Thebans within their gates, and of the sudden occupation of the town, the Plataeans concluded in their alarm that more had entered than was really the case, the night preventing their seeing them. They accordingly came to terms, and accepting the proposal, made no movement; especially as the Thebans offered none of them any violence.

But somehow or other, during the negotiations, they discovered the scanty numbers of the Thebans, and decided that they could easily attack and overpower them; the mass of the Plataeans being averse to revolting from Athens.