after a three days' siege the capital of the Taurini which closed its gates against him, and to induce or terrify into alliance with him all the Ligurian and Celtic communities in the upper basin of the Po, before Scipio, who had taken the command in the Po valley, encountered him.
Scipio in the Valley of the Po
Conflict on the Ticino
The Armies at Placentia
Scipio, who, with an army considerably smaller and very weak in cavalry, had the difficult task of preventing the advance of the superior force of the enemy and of repressing the movements of insurrection which everywhere were spreading among the Celts, had crossed the Po presumably at Placentia, and marched up the river to meet the enemy, while Hannibal after the capture of Turin marched downwards to relieve the Insubres and Boii. In the plain between the Ticino and the Sesia, not far from Vercelli, the Roman cavalry, which had advanced with the light infantry to make a reconnaissance in force, encountered the Punic cavalry sent out for the like purpose, both led by the generals in person. Scipio accepted battle when offered, notwithstanding the superiority of the enemy; but his light infantry, which was placed in front of the cavalry, dispersed before the charge of the heavy cavalry of the enemy, and while the latter engaged the masses of the Roman horsemen in front, the light Numidian cavalry, after having pushed aside the broken ranks of the enemy's infantry, took the Roman horsemen in flank and rear. This decided the combat. The loss of the Romans was very considerable. The consul himself, who made up as a soldier for his deficiencies as a general, received a dangerous wound, and owed his safety entirely to the devotion of his son of seventeen, who, courageously dashing into the ranks of the enemy, compelled his squadron to follow him and rescued his father. Scipio, enlightened by this combat as to the strength of the enemy, saw the error which he had committed in posting himself, with a weaker army, in the plain with his back to the river, and resolved to return to the right bank of the Po under the eyes of his antagonist. As the operations became contracted into a narrower space and his illusions regarding Roman invincibility departed, he recovered the use of his considerable military talents, which the adventurous boldness of his youthful opponent's plans had for a moment paralyzed. While Hannibal was preparing for a pitched battle, Scipio by a rapidly projected and steadily executed march succeeded in reaching the right bank of the river which in an evil hour he had abandoned, and broke down the bridge over the Po behind his army; the Roman detachment of 600 men charged to cover the process of destruction were, however, intercepted and made prisoners. But as the upper course of the river was in the hands of Hannibal, he could not be prevented from marching up the stream, crossing on a bridge of boats, and in a few days confronting the Roman army on the right bank. The latter had taken a position in the plain in front of Placentia; but the mutiny of a Celtic division in the Roman camp, and the Gallic insurrection breaking out afresh all around, compelled the consul to evacuate the plain and to post himself on the hills behind the Trebia. 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, on the wings, the infantry in the centre. The light troops, who formed the vanguard on both sides, began the combat: but the Romans had already almost exhausted their missiles against the cavalry, and immediately gave way. In like manner the cavalry gave way on the wings, hard pressed by the elephants in front, and outflanked right and left by the far more numerous Carthaginian horse. But the Roman infantry proved itself worthy of its name: at the beginning of the battle it fought with very decided superiority against the infantry of the enemy, and even when the repulse of the Roman horse allowed the enemy's cavalry and light-armed troops to turn their attacks against the Roman infantry, the latter, although ceasing to advance, obstinately maintained its ground. At this stage a select Carthaginian band of 1000 infantry, and as many horsemen, under the leadership of Mago, Hannibal's youngest brother, suddenly emerged from an ambush in the rear of the Roman army, and fell upon the densely entangled masses. The wings of the army and the rear ranks of the Roman centre were broken up and scattered by this attack, while the first division, 10,000 men strong, in compact array broke through the Carthaginian line, and made a passage for itself obliquely through the midst of the enemy, inflicting great loss on the opposing infantry and more especially on the Gallic insurgents. This brave body, pursued but feebly, thus reached Placentia. The remaining mass was for the most part slaughtered by the elephants and light troops of the enemy in attempting to cross the river: only part of the cavalry and some divisions of infantry were able, by wading through the river, to gain the camp whither the Carthaginians did not follow them, and thus they too reached Placentia.39 Few battles confer more honour on the Roman soldier than this on the Trebia, and few at the same time furnish graver impeachment of the general in command; although the candid judge will not forget that a commandership in chief expiring on a definite day was an unmilitary institution, and that figs cannot be reaped from thistles. The victory came to be costly even to the victors. Although the loss in the battle fell chiefly on the Celtic insurgents, yet a multitude of the veteran soldiers of Hannibal died afterwards from diseases engendered by that raw and wet winter day, and all the elephants perished except one.
Hannibal Master of Northern Italy
The effect of this first victory of the invading army was, that the national insurrection now spread and assumed shape without hindrance throughout the Celtic territory. The remains of the Roman army of the Po threw themselves into the fortresses of Placentia and Cremona: completely cut off from home, they were obliged to procure their supplies by way of the river. The consul Tiberius Sempronius only escaped, as if by miracle, from being taken prisoner, when with a weak escort of cavalry he went to Rome on account of the elections. Hannibal, who would not hazard the health of his troops by further marches at that inclement season, bivouacked
Polybius's account of the battle on the Trebia is quite clear. If Placentia lay on the right bank of the Trebia where it falls into the Po, and if the battle was fought on the left bank, while the Roman encampment was pitched upon the right—both of which points have been disputed, but are nevertheless indisputable—the Roman soldiers must certainly have passed the Trebia in order to gain Placentia as well as to gain the camp. But those who crossed to the camp must have made their way through the disorganized portions of their own army and through the corps of the enemy that had gone round to their rear, and must then have crossed the river almost in hand-to-hand combat with the enemy. On the other hand the passage near Placentia was accomplished after the pursuit had slackened; the corps was several miles distant from the field of battle, and had arrived within reach of a Roman fortress; it may even have been the case, although it cannot be proved, that a bridge led over the Trebia at that point, and that the -tete de pont- on the other bank was occupied by the garrison of Placentia. It is evident that the first passage was just as difficult as the second was easy, and therefore with good reason Polybius, military judge as he was, merely says of the corps of 10,000, that in close columns it cut its way to Placentia (iii. 74, 6), without mentioning the passage of the river which in this case was unattended with difficulty.
The erroneousness of the view of Livy, which transfers the Phoenician camp to the right, the Roman to the left bank of the Trebia, has lately been repeatedly pointed out. We may only further mention, that the site of Clastidium, near the modern Casteggio, has now been established by inscriptions (Orelli-Henzen, 5117).
