History of the Peloponnesian War

The Athenian generals, finding that some obstacle had arisen, and that they would not be able to take the city by force, immediately proceeded to invest Nisaea; thinking that if they could take it before it was relieved, Megara also would the more quickly surrender.

Now iron, stone-masons. and all other requisites were quickly brought from Athens. So they began from the wall which they occupied, and built a cross-wall on the side of Megara, from the point mentioned down to the sea on each side of Nisaea; the whole army having divided amongst themselves the trench and walls; and they used the stones and bricks from the suburb, and cutting down the fruit trees and timber, strengthened with a palisade whatever point might require it. The houses, too, in the suburb, when provided with battlements, were in themselves a fortification. That whole day they continued working;