History of the Peloponnesian War

They came thus to the battlements in one of the spaces between tower and tower, knowing that there was now no watch kept there. And first came they that carried the ladders and placed them to the wall: then twelve lightly armed, only with a dagger and a breastplate, went up, led by Ammeas the son of Coroebus, who was the first that mounted; and they that followed him went up into either tower six. To these succeeded others lightly armed that carried the darts for whom they that came after carried targets at their backs that they might be the more expedite to get up, which targets they were to deliver to them when they came to the enemy.

At length, when most of them were ascended, they were heard by the watchmen that were in the towers.