Titus Livius (Livy), The History of Rome, Book 24
Frank Gardener Moore, Professor Emeritus in Columbia University, Ed.

35. Meanwhile Marcellus set out with about a third of his army to recover the cities which in the unsettled state of affairs had gone over to the Carthaginians. [2] Helorus and Herbesus he did recover by their own surrender; Megara he took by assault, destroyed and plundered, to terrify the others and especially the Syracusans. [3] About the same time also Himilco, who had long kept his fleet off the promontory of Pachynum, landed at Heraclea,¹ called Minoa, 25,000 infantry, 3,000 cavalry and twelve elephants, a very much larger force than that with which he had previously kept his fleet off Pachynum. [4] But after Syracuse had been seized by Hippocrates, Himilco went to Carthage and was aided there both by the legates of Hippocrates and by a letter from Hannibal, who said the time had come to recover Sicily in the most honourable manner. [5] Himilco [p. 289]himself, being an influential adviser, present in² person, had easily prevailed upon them to send across to Sicily the largest possible forces of infantry and cavalry. Arrived at Heraclea, he recovered Agrigentum within a few days. [6] And the hopes of the other city-states which were on the side of the Carthaginians were so fired to drive the Romans out of Sicily that finally even those who were besieged at Syracuse took courage. [7] And thinking the city could be sufficiently defended by a part of the forces, they so divided the military duties that Epicydes should be in charge of the defence of the city, and Hippocrates, together with Himilco, should carry on the war against the Roman consul. [8] With 10,000 infantry and five hundred horse he set out by night through places unguarded and pitched camp near the city of Acrillae.³ [9] As they were fortifying, Marcellus arrived, returning from Agrigentum, which was already occupied, since it was in vain that he had endeavoured to anticipate the enemy by hastening thither. Nothing was farther from his thoughts than that a Syracusan army should meet him there at that time. [10] Nevertheless, from fear of Himilco and the Carthaginians, being no match for them with the forces he had, he was advancing with all possible alertness and with a column so formed as to meet any emergency.