History of the Peloponnesian War

The Athenian commanders, knowing some cross accident had happened and that they could not take the city by assault, fell to enclosing of Nisaea with a wall, which if they could take before aid came, they thought Megara would the sooner yield. Iron was quickly brought unto them from Athens, and masons, and whatsoever else was necessary.

And beginning at the wall they had won, when they had built cross over to the other side, from thence both ways they drew it on to the sea on either side Nisaea; and having distributed the work amongst the army, as well the wall as the ditch, they served themselves of the stones and bricks of the suburbs, and having felled trees and timber, they supplied what was defective with a strong palisade. The houses also themselves of the suburbs, when they had put on battlements, served them for a fortification. All that day they wrought;

the next day about evening they had within very little finished. But then they that were in Nisaea, seeing themselves to want victual (for they had none but what came day by day from the city above), and without hope that the Peloponnesians could quickly come to relieve them, conceiving also that the Megareans were their enemies, compounded with the Athenians on these terms: to be dismissed every one at a certain ransom in money; to deliver up their arms; and the Lacedaemonians, both the captain and whosoever of them else was within, to be at discretion of the Athenians. Having thus agreed, they went out.

And the Athenians, when they had broken off the long walls from the city of Megara and taken in Nisaea, prepared for what was further to be done.