History of the Peloponnesian War

After a good many had mounted they were discovered by the sentinels in the towers, by the noise made by a tile which was knocked down by one of the Plataeans as he was laying hold of the battlements.

The alarm was instantly given, and the troops rushed to the wall, not knowing the nature of the danger, owing to the dark night and stormy weather; the Plataeans in the town having also chosen that moment to make a sortie against the wall of the Peloponnesians upon the side opposite to that on which their men were getting over, in order to divert the attention of the besiegers.

Accordingly they remained distracted at their several posts, without any venturing to stir to give help from his own station, and at a loss to guess what was going on.

Meanwhile the three hundred set aside for service on emergencies went outside the wall in the direction of the alarm. Fire-signals of an attack were also raised towards Thebes;

but the Plataeans in the town at once displayed a number of others, prepared beforehand for this very purpose, in order to render the enemy's signals unintelligible, and to prevent his friends getting a true idea of what was passing and coming to his aid, before their comrades who had gone out should have made good their escape and be in safety.