History of the Peloponnesian War

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.