So Hannibal, having failed in this essay also, came by night to Cannæ, and since he knew the place as one fit for ambuscades and for a pitched battle, he encamped there. And first he ploughed the whole site over, because it had a sandy subsoil and his object was to have a cloud of dust raised in the conflict; the wind generally springs up there in summer toward noon, and he contrived to get it behind his back. The consuls seeing at dawn that his stockade was empty of men at first waited, apprehending ambush, but later in the broad daylight came to Cannæ. Each of the Roman leaders bivouacked apart beside the river, for since they were not congenial they avoided association together. Paulus remained quiet, but Terentius was anxious to force the issue; when he saw, however, that the soldiers were rather listless, he gave up the idea. But Hannibal, who was determined to goad them into battle even against their will, shut them off from their sources of water, prevented their scattering into small parties, and threw the bodies of the slain into the stream above their intrenchments and in plain sight, in order to disgust them with the drinking supply. Then the Romans started to array themselves for battle. Hannibal anticipating this movement had planted ambuscades at the foot of the hills but held the remainder of his army drawn up. He also ordered some men at a given signal to simulate desertion; they were to throw away their shields and spears and larger swords but secretly to retain their daggers, so that after his antagonists had received them as unarmed, they might attack them unexpectedly.
The Romans having had in view since early morning the troops arrayed about Hannibal were now arming themselves and taking their places. The trumpets incited both parties, the signals were raised, and then ensued the clash of battle and a contest which assumed a variety of aspects. Until noon the advantage had not fallen distinctly to either side. Then the wind came up and the false deserters were received as men destitute of arms and got behind the Romans, alleging the very natural reason that they wanted to be out of the way of the Carthaginian attack. At this moment the men rose from ambush on both sides, Hannibal with his cavalry charged the front ranks, the enemy confused the Romans on every hand, the wind and the dust cloud assailed their faces violently, causing perplexity, and interfered with their breathing, which was already growing quick and labored from exertion, so that deprived of sight, deprived of voice, they perished in a wild mêlée, preserving no semblance of order. So great a multitude fell that Hannibal did not even try to find out the number of the common people, and in regard to the number of the knights and members of the senate he did not write to the Carthaginians at home but indicated it by the finger-rings; these he measured off by the quart and sent away. Only the senators and the knights wore finger-rings. Yet after all a number made good their escape even on this occasion, among them Terentius; Paulus was killed. Hannibal did not pursue nor did he hasten to Rome. He might have set out at once for Rome with either his entire army or at least a portion of it and have quickly ended the war; yet he did not do so, although Maharbal urged him to do so. Hence he was censured as being able to win victories but not understanding how to use them. Since they had delayed this time, they could never again have an opportunity to make haste. Therefore Hannibal regretted it, feeling that he had committed a blunder, and was ever crying out: "Oh Cannæ, Cannæ!"