Thucydides, History of the Peloponnesian War
Benjamin Jowett, Ed.

102. Meanwhile the Syracusans who fled first into the city, observing the resistance made by the¹ left wing, took courage, and coming out drew up against that part of the Athenian line which was opposed to them. They also sent a detachment against the wall of circumvallation² on Epipolae, supposing that it was undefended, and might be taken. [2] They did indeed take and demolish the outwork, which was about a thousand feet in length; but Nicias, who happened to have been left there because he was ill, saved the lines³ themselves. He commanded the attendants of the camp to set fire to the engines and to the timber which had been left lying in front of the wall, for being without troops he knew that there was no other way of escape. [3] The expedient succeeded; and in consequence of the fire the Syracusans gave up the attack. The Athenian army too was now hastening from the plain to the surrounding wall⁴, with the intention of beating off the enemy; while the ships, as they had been ordered, were sailing from Thapsus into the Great Harbour. [4] The Syracusans on the heights, seeing this combined movement, quickly retreated, together with the rest of the army, into the city, thinking that with their present force they were no longer able to prevent the completion of the line of wall towards the sea.