History of the Peloponnesian War

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.