Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

130. On the following day the Athenians sailed round to the side of Mendè looking towards Scionè;¹ they took the suburb, and during the whole of that day devastated the country. No one came out to meet them; for a division had arisen in the city, and on the following night the three hundred Scionaeans returned home. [2] On the next day Nicias with half his army went as far as the Scionaean frontier and devastated the country on his march, while Nicostratus with the other half sat down before the upper gates of Mendè, out of which the road leads to Potidaea. [3] In this part of the city within the walls the Mendaeans and their allies chanced to have their arms deposited, and Polydamidas, arraying his forces in order of battle, was just exhorting the Mendaeans to go forth. [4] Some one of the popular faction answered in the heat of party that he would not go out, and that he did not care to fight, but no sooner had he uttered the words than he was seized by the Peloponnesian commander and roughly handled. Whereupon the people lost patience, caught up their arms, and made a furious rush upon the Peloponnesians and the opposite party who were in league with them. [5] They soon put them to flight, partly because the onslaught was sudden, and also because the gates were thrown open to the Athenians, which greatly terrified them. [6] For they thought that the attack upon them was premeditated. All the Peloponnesians who were not killed on the spot fled to the citadel, which they had previously kept in their own hands. Nicias had now returned and was close to the city, and the Athenians rushed into Mendè with their whole force. As the gates had been opened without any previous capitulation they plundered the town as if it had been stormed; and even the lives of the citizens were with difficulty saved by the efforts of the generals. [7] The Mendaeans were then told that they were to retain their former constitution, and bring to trial among themselves any whom they thought guilty of the revolt. At the same time the Athenians blockaded the garrison in the Acropolis by a wall extending to the sea on either side and established a guard. Having thus secured Mendè, they proceeded against Scionè.