Hannibal pitched his camp on the Nure, about five miles from Piacenza, but Scipio remained immovable in his lines waiting for the arrival of his colleague.  Hannibal’s position was a difficult one.  He had traversed the Pyrenees and the Alps that he might attack Rome; but between him and Southern Italy lay yet another barrier, the Apennines.  Scipio had missed him after he had crossed the Pyrenees, had been too late to attack him when, exhausted and worn out, his army emerged from the Alps; but now, united with Sempronius, he hoped to crush him at the foot of the Apennines.  Hannibal wished, if possible, to prevent a junction of the two Roman armies, but if that could not be done he determined to fight them together.

Scipio perceived the danger of his position; and in order to be able the better to join Sempronius he left Piacenza under cover of night, and took up a strong position on the banks of the Trebia.  Here he could maintain his communications direct with Rome, and, if absolutely necessary, fall back and join his colleague advancing towards him.  Hannibal, when he perceived Scipio’s change of position, broke up his camp and took post on the Trebiola, a little stream running into the Trebia and facing the Roman camp at a distance of four miles.

He was now powerless to prevent the junction of the two Roman armies, and for nearly a month Scipio and Hannibal lay watching each other.  By that time Sempronius was within a day’s march of Scipio.  Hannibal had not been idle during this time of rest.  He had been occupied in cementing his alliance with the Gaulish tribes inhabiting the Lombard plains.  These, seeing how rapidly Hannibal had cleared the province of the Romans, believed that their deliverance would be accomplished, and for the most part declared for the Carthaginians.

Hannibal’s agents had also been at work at Clastidium, and the prefect of the garrison was induced by a bribe to surrender the place to him.  This was of enormous advantage to Hannibal, and a corresponding blow to the Romans, for Clastidium was the chief magazine north of the Apennines.  The news of the fall of this important place filled Sempronius, an energetic and vigorous general, with fury.  He at once rode down from his camp to that of Scipio and proposed that Hannibal should be attacked instantly.

Scipio, who was still suffering from the wound he had received in the cavalry engagement, urged that the Roman army should remain where they were, if necessary, through the coming winter.  He pointed out that Hannibal’s Gaulish allies would lose heart at seeing him inactive, and would cease to furnish him with supplies, and that he would be obliged either to attack them at a disadvantage or to retire from the position he occupied.  But Sempronius was an ambitious man, the time for the consular election was approaching, and he was unwilling to leave for his successor the glory of crushing Hannibal.