This was accomplished without notable loss, because the Numidian horsemen sent in pursuit lost their time in plundering, and setting fire to, the abandoned camp.  In this strong position, with his left wing resting on the Apennines, his right on the Po and the fortress of Placentia, and covered in front by the Trebia—­no inconsiderable stream at that season—­Scipio was unable to save the rich stores of Clastidium (Casteggio) from which in this position he was cut off by the army of the enemy; nor was he able to avert the insurrectionary movement on the part of almost all the Gallic cantons, excepting the Cenomani who were friendly to Rome; but he completely checked the progress of Hannibal, and compelled him to pitch his camp opposite to that of the Romans.  Moreover, the position taken up by Scipio, and the circumstance of the Cenomani threatening the borders of the Insubres, hindered the main body of the Gallic insurgents from directly joining the enemy, and gave to the second Roman army, which meanwhile had arrived at Ariminum from Lilybaeum, the opportunity of reaching Placentia through the midst of the insurgent country without material hindrance, and of uniting itself with the army of the Po.

Battle on the Trebia

Scipio had thus solved his difficult task completely and brilliantly.  The Roman army, now close on 40,000 strong, and though not a match for its antagonist in cavalry, at least equal in infantry, had simply to remain in its existing position, in order to compel the enemy either to attempt in the winter season the passage of the river and an attack upon the camp, or to suspend his advance and to test the fickle temper of the Gauls by the burden of winter quarters.  Clear, however, as this was, it was no less clear that it was now December, and that under the course proposed the victory might perhaps be gained by Rome, but would not be gained by the consul Tiberius Sempronius, who held the sole command in consequence of Scipio’s wound, and whose year of office expired in a few months.  Hannibal knew the man, and neglected no means of alluring him to fight.  The Celtic villages that had remained faithful to the Romans were cruelly laid waste, and, when this brought on a conflict between the cavalry, Hannibal allowed his opponents to boast of the victory.  Soon thereafter on a raw rainy day a general engagement came on, unlocked for by the Romans.  From the earliest hour of the morning the Roman light troops had been skirmishing with the light cavalry of the enemy; the latter slowly retreated, and the Romans eagerly pursued it through the deeply swollen Trebia to follow up the advantage which they had gained.  Suddenly the cavalry halted; the Roman vanguard found itself face to face with the army of Hannibal drawn up for battle on a field chosen by himself; it was lost, unless the main body should cross the stream with all speed to its support.  Hungry, weary, and wet, the Romans came on and hastened to form in order of battle, the cavalry, as usual,