As soon as Hannibal was apprised in the morning that Scipio and his forces had left their ground, he pressed on after them, very earnest to overtake them before they should reach the rivers but he was too late. The main body of the Roman army had got over. There was, however, a detachment of a few hundred men, who had been left on Hannibal’s side of the river to guard the bridge until all the army should have passed, and then to help in cutting it away. They had accomplished this before. Hannibal’s arrival, but had not had time to contrive any way to get across the river themselves. Hannibal took them all prisoners.
The condition and prospects of both the Roman and Carthaginian cause were entirely changed by this battle and the retreat of Scipio across the Po. All the nations of the north of Italy, who had been subjects or allies of the Romans, now turned to Hannibal. They sent embassies into his camp, offering him their friendship and alliance. In fact, there was a large body of Gauls in the Roman camp, who were fighting under Scipio at the battle of Ticinus, who deserted his standard immediately afterward, and cave over in a mass to Hannibal. They made this revolt in the night, and, instead of stealing away secretly, they raised a prodigious tumult, killed the guards, filled the encampment with their shouts and outcries, and created for a time an awful scene of terror.
Hannibal received them, but he was too sagacious to admit such a treacherous horde into his army. He treated them with great consideration and kindness, and dismissed them with presents, that they might all go to their respective homes, charging them to exert their influence in his favor among the tribes to which they severally belonged.
Hannibal’s soldiers, too, were very much encouraged by the commencement they had made. The army made immediate preparations for crossing the river. Some of the soldiers built rafts; others went up the stream in search of places to ford. Some swam across. They could adopt these or any other modes in safety, for the Romans made no stand on the opposite bank to oppose them, but moved rapidly on, as fast as Scipio could be carried. His wounds began to inflame, and were extremely painful.
In fact, the Romans were dismayed at the danger which now threatened them. As soon as news of these events reached the city, the authorities there sent a dispatch immediately to Sicily to recall the other consul. His name was Sempronius. It will be recollected that, when the lots were cast between him and Scipio, it fell to Scipio to proceed to Spain, with a view to arresting Hannibal’s march, while Sempronius went to Sicily and Africa. The object of this movement was to threaten and attack the Carthaginians at home, in order to distract their attention and prevent their sending any fresh forces to aid Hannibal, and, perhaps, even to compel them to recall hire from Italy to defend their own capital. But now that Hannibal had not only passed the Alps, but had also crossed the Po, and was marching toward Rome-Scipio himself disabled and his army flying before him they were obliged at once to abandon the plan of threatening Carthage. They sent with all dispatch an order to Sempronius to hasten home and assist in the defense of Rome.
Sempronius was a man of a very prompt and impetuous character, with great confidence in his own powers, and very ready for action. He came immediately into Italy, recruited new soldiers for the army, put himself at the head of his forces, and marched northward to join Scipio in the valley of the Po. Scipio was suffering great pain from his wound, and could do but little toward directing the operations of the army. He had slowly retreated before Hannibal, the fever and pain of his wound being greatly exasperated by the motion of traveling. In this manner he arrived at the Trebia, a small stream flowing northward into the Po. He crossed this stream, and finding that he could not go any further, on account of the torturing pain to which it put him to be moved, he halted his army, marked out an encampment, threw up fortifications around it, and prepared to make a stand. To his great relief, Sempronius soon came up and joined him here.