History of the Peloponnesian War

They made ladders to suit the height of the enemy's wall, measuring by the layers of bricks, where the wall looking toward them happened to be imperfectly whitewashed. Now many counted the layers at the same time; and though some would naturally miss the correct calculation, the majority would attain it; especially as they counted them many times over, and were also at no great distance, but the wall was easily observed by them as far as they wished.

In this way they ascertained the proper length of the ladders, guessing the measure from the thickness of the bricks.

Now the wall of the Peloponnesians was of the following construction. It consisted of two lines round the place, one against the Plataeans, and another in case any one should attack them on the outside from Athens; and the lines were about sixteen feet apart.

In this interval then of the sixteen feet there were quarters built, and partitioned out amongst the soldiers that were on guard; and these were continuous, so that it appeared but one thick wall, with battlements on each side.

At the distance of every ten battlements there were towers, of considerable size, and of the same breadth as the wall, reaching both to its inner and its outer front, so that there was no passage by the side of a tower, but they passed through the middle of them.

During the nights therefore, whenever it was stormy and wet weather, they used to leave the battlements, and to keep watch from the towers, as they were only at a short distance one from another, and were covered in above. Such then was the nature of the wall by which the Plataeans were enclosed.

When they had made their preparations, having watched for a stormy night of wind and rain, and at the same time moonless, they went forth under the guidance of those who had been the authors of the enterprise. In the first place then they crossed the ditch which ran round their city, and then came up to the enemy's wall, unperceived by the sentinels; for they did not see before them in the dark, and did not hear them owing to the wind, which drowned with its clatter the noise of their approach;