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

42. But in the midst of their preparations Demosthenes and Eurymedon arrived with the Athenian¹ reinforcements. They brought a fleet, including foreign ships, of about seventy-three sail, carrying five thousand heavy infantry of their own and of their allies, numerous javelin-men, slingers, and archers, both Hellenic and Barbarian, and abundant supplies of every kind. The Syracusans and their allies were in consternation. [2] It seemed to them as if their perils would never have an end when they saw, notwithstanding the fortification of Decelea, another army arriving nearly equal to the former, and Athens displaying such varied and exuberant strength; while the first Athenian army regained a certain degree of confidence after their disasters. Demosthenes at once saw how matters stood; he knew that there was no time to be lost, and resolved that it should not be with him as it had been with Nicias. [3] For Nicias was dreaded at his first arrival, but when, instead of at once laying siege to Syracuse, he passed the winter at Catana, he fell into contempt, and his delay gave Gylippus time to come with an army from Peloponnesus. Whereas if he had struck hard at first, the Syracusans would never even have thought of getting fresh troops; strong in their own self-sufficiency, they would have discovered their inferiority only when the city had been actually invested, and then, if they had been sent for reinforcements, they would have found them useless. Demosthenes, reflecting on all this, and aware that he too would never again be in a position to inspire such terror as on the day of his arrival, desired to take the speediest advantage of the panic caused by the appearance of his army. [4] Accordingly, seeing that the cross-wall of the Syracusans which had prevented the Athenians from investing them was but a single line, and that if he could gain the command of the way up to Epipolae and take the camp which was on the high ground the wall would be easily captured, for no one would so much as stand his ground against them, he resolved to make the attempt at once. [5] This would be the shortest way of putting an end to the war. If he succeeded, Syracuse would fall into his hands; if he failed, he meant to bring away the expedition; [6] he would no longer wear out the Athenian army, and weaken the state to no purpose.

The Athenians began by ravaging the fields of the Syracusans about the Anapus, and regained their former superiority both by sea and land. At sea the Syracusans no longer opposed them; and on land they merely sent out parties of cavalry and javelin-men from the Olympieum.