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.
But it was the fortune of Demosthenes to be for the most part in more continual trouble because, being far in the rear on the retreat, the enemy pressed upon him first, and now also, when he saw the Syracusans in pursuit, he was more taken up with ordering his troops for battle than with pressing forward, and so wasted time until he was surrounded by the enemy and both he and his men were in a state of utter confusion. For huddled together in a plot of ground surrounded by a wall, on either side of which a road passed, there being inside the wall a considerable number of olive trees, they were pelted with missiles from every side.
And the Syracusans had good reason to adopt attacks of this kind rather than contests at close quarters; for to risk their lives against men in despair was not now to their advantage, so much as to that of the Athenians. Besides, they considered that success was already assured; therefore everyone spared himself somewhat, not wishing to throw away his life before the end, and they all thought that even as it was, and following this manner of fighting, they would subdue and capture the enemy.
And so when they had assailed the Athenians and their allies with missiles from all sides throughout the day and saw that they were at length worn out by reason of their wounds and general misery, Gylippus and the Syracusans and their allies made proclamation, first, that any of the islanders[*](cf. 7.57.4, ὑπήκοοι ὐντες καὶ ἀνάγκῃ . . . ἠκολούθουν) who so wished might come over to their side on a guarantee of freedom;
and some states, but only a few, came over. Afterwards, however, an agreement was made with all the rest of the troops under Demosthenes that if they would surrender their arms no one should suffer death either by violence or by imprisonment or by deprivation of the bare necessities of life.
So they all surrendered, six thousand in number; and they gave up all the money they had, casting it into upturned shields; and four of these were filled. These captives the Syracusans immediately took to the city; as for Nicias and his men, they reached the river Erineus that same day, and after crossing it Nicias encamped his army on a height.