History of the Peloponnesian War
Thucydides
Thucydides, Vol. 1-4. Smith, Charles Foster, translator. London and Cambridge, MA: Heinemann and Harvard University Press, 1919-1923.
Seeing these things, the men on the heights and the main army of the Syracusans hastily withdrew into the city, thinking that with the force they then had at their disposal they could no longer prevent the building of the wall to the sea.
After this the Athenians set up a trophy and restored their dead to the Syracusans under truce, themselves getting back the bodies of Lamachus and his men. The whole of their armament being now present, both fleet and land-force, starting from the bluff of Epipolae they proceeded to cut off the Syracusans by a double wall down to the sea.
Provisions were coming in for the army from all quarters of Italy. And there came also as allies to the Athenians many of the Sicels, who before had been hesitating, and from Tyrrhenia three fifty-oared galleys. And other matters were progressing according to their hopes.
For the Syracusans no longer thought they could win at war, as no aid had come to them even from the Peloponnesus; and indeed they were discussing terms of agreement, not only among themselves, but even with Nicias, who now since the death of Lamachus had sole command.