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

39. Dismissed immediately after this exhortation, they took food and rest. On the following day they were posted in different places, to occupy the roads and close the ways of escape. The majority took their positions above and around the theatre, being already familiar with the sight of an assembly. [2] The Roman commandant, being brought before the people by the magistrates, said that right and authority in the matter belonged to the consul, not to himself, and in general the same things he had said the day before. [3] And at first insensibly and only a few, presently a larger number, then all, now with one voice kept bidding him to deliver the keys; and when he delayed and postponed, they repeated savage threats and apparently would not further postpone violence, their last resort. [4] Thereupon the prefect gave the signal with his toga, as had been agreed, and the soldiers, alert and ready long before, dashed down, some of them from above, upon the rear of the assembly with a shout, while others, massed at the exits of the theatre, blocked the way. [5] The men of Henna, shut up in the cavea, were slain and piled together not only owing to the slaughter, but also by the panic, since they rushed down over each others' heads, and as the unharmed fell upon the wounded, the living upon the dead, they were lying in heaps. [6] Thence the soldiers scattered in every direction, and, just as in a captured city, flight and slaughter were in complete possession, while the wrath of the soldiers was not a whit less intense because they were slaying an unarmed [p. 301]crowd, than if equal danger and ardour for the fray¹ were spurring them on. [7] So by an act, it may have been criminal, it may have been unavoidable, Henna was held.

Marcellus, without reproving the act, allowed the soldiers to plunder the Hennensians, thinking the frightened Sicilians had been deterred from betraying their garrisons. [8] And as was natural in the case of a city in the heart of Sicily and famous, whether for the remarkable natural defences of its site, or as hallowed everywhere by the footprints of Proserpina, long ago carried away,² news of the massacre made its way over the whole of Sicily almost in a single day. [9] And then in truth, since they thought that the abode, not of men only but also of gods, had been desecrated by an atrocious massacre, even those who till then had wavered went over to the Carthaginians. [10] Hippocrates thereupon went back to Murgantia, Himilco to Agrigentum, after bringing up their army to Henna to no purpose at the summons of the traitors. [11] Marcellus returned to Leontini, had grain and other supplies brought into the camp, left a suitable garrison there and came to Syracuse to carry on the siege. [12] He then relieved Appius Claudius, to sue for the consulship at Rome, and in his place put Titus Quinctius Crispinus in command of the fleet and the old camp.³ [13] As for himself, he fortified and built winter quarters five miles from the Hexapylon — Leon they call the place. Such were the events in Sicily up to the beginning of the winter.