Titus Livius (Livy), The History of Rome, Book 26
Frank Gardner Moore, Professor Emeritus in Columbia University, Ed.

46. on the landward side it was a very serious¹ task for men approaching the walls; and they were hindered not only by the height of these, but also because the defenders had the attacking Romans doubly exposed to wounds on the right and on the left, so that as they approached their sides were in greater danger than the front of their bodies. [2] but on the other side of the city the five hundred found both an easy passage across the lagoon and then an easy climb to the top of the wall. [3] for it had not been built up to the full height, since they had sufficient confidence in the protection offered by the position itself and by the lagoon, and there was no post of armed men nor a guard to confront them, since all were intent upon bringing aid to any quarter from which danger was indicated.

having entered the city without a struggle, they then proceeded with all possible speed to the gate round which the whole battle had been brought on. [4] on that fighting so intent were not only the minds, but also [5??] the eyes and ears of all the fighters and spectators and of those who were encouraging the fighters, that no one was aware that the city had been captured in their rear until missiles fell upon their backs and they had the enemy on both front and rear. [6] then as the defenders were panic —stricken, the walls were captured and men began to batter down the gate at the same time from within and from without. and presently, when the gates had been chopped to pieces and dragged off, so as not to block the passage, the armed men charged. [7] a great multitude climbed over the wall also, but they scattered in all directions to slay the townspeople. the regular formation which had entered the gate made its way with its [p. 179]officers and its ranks through the centre of the city² even into the market —place. [8] from that point Scipio saw the enemy fleeing down two streets, one party towards the hill facing the east³ and held by a garrison of five hundred soldiers, the rest into the citadel, into which Mago also with nearly all the armed men who had been beaten back from the walls had fled for refuge. accordingly he sent part of his forces to storm the hill, and himself led a part to the citadel. [9] the hill was taken at the first assault, and Mago, who attempted to defend the citadel, seeing the whole city filled with the enemy and that there was no hope, surrendered himself and the citadel with its garrison. [10] until the surrender of the citadel there was slaughter everywhere throughout the city, and they did not spare any adult who met them. then the signal was given and an end was made of slaughter. the victors turned to the spoils, which were immense and of every kind.