History of the Peloponnesian War

Falling upon them they put them to rout, partly by the suddenness of their onslaught, partly because the others were terrified when the gates were opened to the Athenians; for they thought that the attack had been made upon them by a preconcerted agreement.

Those of the Peloponnesians who were not killed on the spot took refuge on the acropolis, which they already had possession of; but the Athenians—for Nicias had already turned back and was near the city— burst into the city with their whole force, and, as the gates had been opened without an agreement, plundered the city as though they had taken it by storm; and the generals with difficulty kept them from destroying the inhabitants also.

They then directed the Mendaeans henceforth to retain their former constitution, and bring to trial among themselves any whom they thought guilty of the revolt; but the men on the acropolis they fenced off with a wall extending on either side down to the sea, and set a guard over them. And when they had thus secured Mende, they proceeded against Scione.