Titus Livius (Livy), The History of Rome, Book 23
D. Spillan, A.M., M.D., Cyrus Evans, Ed.

17. When Hannibal, all hope of getting possession of Nola being lost, had retired to Acerrae, Marcellus, having closed the gates and posted guards in different quarters to prevent any one from going out, immediately instituted a judicial inquiry in the forum, into the conduct of those who had been secretly in communication with the enemy. [2] He beheaded more than seventy who were convicted of treason, and ordered their goods to be confiscated to the Roman state; [3] and then committing the government to the senate, set out with all his forces, and, pitching a camp, took up a position above Suessula. [4] The Carthaginian, having at first endeavoured to win over the people of Acerrae to a voluntary surrender, but finding them resolved, makes preparations for a siege and assault. But the people of Acerrae had more spirit than power. [5] Despairing, therefore, of the defence of the city, when they saw their walls being circumvallated, before the lines of the enemy were completed, they stole off in the dead of night through the opening in the works, and where the watches had been neglected; [6] and pursuing their course through roads and pathless regions, accordingly as design or mistake directed each, made their escape to those towns of Campania which they knew had not renounced their fidelity. [7] After Acerrae was plundered and burnt, Hannibal, having received intelligence that the Roman dictator with the new-raised legions was seen at some distance from Casilinum, and fearing lest, the camp of the enemy being so near, something might occur at Capua, marched his army to Casilinum. [8] At that time Casilinum was occupied by five hundred Praenestines, with a few Romans and Latins, whom the news of the defeat at Cannae had brought to the same place. [9] These men setting out from home too late, in consequence of the levy at Praeneste not being completed at the appointed day, and arriving at Casilinum before the defeat was known there, where they united themselves with other troops, Romans and allies, were proceeding thence in a tolerably large body, but the news of the battle at Cannae turned them back to Casilinum. [10] Having spent several days [p. 856]there in evading and concerting plots, in fear themselves and suspected by the Campanians, and having now received certain information that the revolt of Capua and the reception of Hannibal were in agitation, they put the townsmen to the sword by night, and seized upon the part of the town on this side the Vulturnus, for it is divided by that river. [11] Such was the garrison the Romans had at Casilinum; to these was added a cohort of Perusians, in number four hundred and sixty, who had been driven to Casilinum by the same intelligence which had brought the Praenestines a few days before. [12] They formed a sufficient number of armed men for the defence of walls of so limited extent, and protected on one side by the river. The scarcity of corn made them even appear too numerous.