As soon as the winter snows were thawed, Hasdrubal commenced his march from Auvergne to the Alps. He experienced none of the difficulties which his brother had met with from the mountain tribes. Hannibal's army had been the first body of regular troops that had ever traversed their regions; and, as wild animals assail a traveller, the natives rose against it instinctively, in imagined defence of their own habitations, which they supposed to be the objects of Carthaginian ambition. But the fame of the war, with which Italy had now been convulsed for twelve years, had penetrated into the Alpine passes, and the mountaineers now understood that a mighty city southward of the Alps was to be attacked by the troops whom they saw marching among them. They now not only opposed no resistance to the passage of Hasdrubal, but many of them, out of love of enterprise and plunder, or allured by the high pay that he offered, took service with him; and thus he advanced upon Italy with an army that gathered strength at every league. It is said, also, that some of the most important engineering works which Hannibal had constructed were found by Hasdrubal still in existence, and materially favored the speed of his advance. He thus emerged into Italy from the Alpine valleys much sooner than had been anticipated. Many warriors of the Ligurian tribes joined him; and, crossing the River Po, he marched down its southern bank to the city of Placentia, which he wished to secure as a base for his future operations. Placentia resisted him as bravely as it had resisted Hannibal twelve years before, and for some time Hasdrubal was occupied with a fruitless siege before its walls.
Six armies were levied for the defence of Italy when the long-dreaded approach of Hasdrubal was announced. Seventy thousand Romans served in the fifteen legions of which, with an equal number of Italian allies, those armies and the garrisons were composed. Upward of thirty thousand more Romans were serving in Sicily, Sardinia, and Spain. The whole number of Roman citizens of an age fit for military duty scarcely exceeded a hundred and thirty thousand. The census taken before the commencement of the war had shown a total of two hundred and seventy thousand, which had been diminished by more than half during twelve years. These numbers are fearfully emphatic of the extremity to which Rome was reduced, and of her gigantic efforts in that great agony of her fate. Not merely men, but money and military stores, were drained to the utmost, and if the armies of that year should be swept off by a repetition of the slaughters of Thrasymene and Cannae all felt that Rome would cease to exist.
Even if the campaign were to be marked by no decisive success on either side her ruin seemed certain. In South Italy, Hannibal had either detached Rome's allies from her or had impoverished them by the ravages of his army. If Hasdrubal could have done the same in Upper Italy; if Etruria, Umbria, and Northern Latium had either revolted or been laid waste, Rome must have sunk beneath sheer starvation, for the hostile or desolated territory would have yielded no supplies of corn for her population, and money to purchase it from abroad there was none. Instant victory was a matter of life or death. Three of her six armies were ordered to the North, but the first of these was required to overawe the disaffected Etruscan. The second army of the North was pushed forward, under Porcius, the praetor, to meet and keep in check the advanced troops of Hasdrubal; while the third, the grand army of the North, which was to be under the immediate command of the consul Livius, who had the chief command in all North Italy, advanced more slowly in its support. There were similarly three armies in the South, under the orders of the other consul, Claudius Nero.
The lot had decided that Livius was to be opposed to Hasdrubal, and that Nero should face Hannibal. And "when all was ordered as themselves thought best, the two consuls went forth from the city, each his several way. The people of Rome were now quite otherwise affected than they had been when L. Æmilius Paulus and C. Terentius Varro were sent against Hannibal. They did no longer take upon them to direct their generals, or bid them despatch and win the victory betimes, but rather they stood in fear lest all diligence, wisdom, and valor should prove too little; for since few years had passed wherein some one of their generals had not been slain, and since it was manifest that, if either of these present consuls were defeated or put to the worst, the two Carthaginians would forthwith join, and make short work with the other, it seemed a greater happiness than could be expected that each of them should return home victor, and come off with honor from such mighty opposition as he was like to find. With extreme difficulty had Rome held up her head ever since the battle of Cannae; though it were so, that Hannibal alone, with little help from Carthage, had continued the war in Italy. But there was now arrived another son of Hamilcar, and one that in his present expedition had seemed a man of more sufficiency than Hannibal himself; for whereas, in that long and dangerous march through barbarous nations, over great rivers and mountains that were thought unpassable, Hannibal had lost a great part of his army, this Hasdrubal, in the same places, had multiplied his numbers, and gathering the people that he found in the way, descended from the Alps like a rolling snowball, far greater than he came over the Pyrenees at his first setting out of Spain. These considerations and the like, of which fear presented many unto them, caused the people of Rome to wait upon their consuls out of the town, like a pensive train of mourners, thinking upon Marcellus and Crispinus, upon whom, in the like sort, they had given attendance the last year, but saw neither of them return alive from a less dangerous war. Particularly old Q. Fabius gave his accustomed advice to M. Livius, that he should abstain from giving or taking battle until he well understood the enemy's condition. But the consul made him a froward answer, and said that he would fight the very first day, for that he thought it long till he should either recover his honor by victory, or, by seeing the overthrow of his own unjust citizens, satisfy himself with the joy of a great though not an honest revenge. But his meaning was better than his words."
Hannibal at this period occupied with his veteran but much-reduced forces the extreme south of Italy. It had not been expected either by friend or foe that Hasdrubal would effect his passage of the Alps so early in the year as actually occurred. And even when Hannibal learned that his brother was in Italy, and had advanced as far as Placentia, he was obliged to pause for further intelligence before he himself commenced active operations, as he could not tell whether his brother might not be invited into Etruria, to aid the party there that was disaffected to Rome, or whether he would march down by the Adriatic Sea. Hannibal led his troops out of their winter quarters in Bruttium, and marched northward as far as Canusium. Nero had his head-quarters near Venusia, with an army which he had increased to forty thousand foot and two thousand five hundred horse, by incorporating under his own command some of the legions which had been intended to act under other generals in the South. There was another Roman army, twenty thousand strong, south of Hannibal at Tarentum. The strength of that city secured this Roman force from any attack by Hannibal, and it was a serious matter to march northward and leave it in his rear, free to act against all his depots and allies in the friendly part of Italy, which for the two or three last campaigns had served him for a base of his operations. Moreover, Nero's army was so strong that Hannibal could not concentrate troops enough to assume the offensive against it without weakening his garrisons and relinquishing, at least for a time, his grasp upon the southern provinces. To do this before he was certainly informed of his brother's operations would have been a useless sacrifice, as Nero could retreat before him upon the other Roman armies near the capital, and Hannibal knew by experience that a mere advance of his army upon the walls of Rome would have no effect on the fortunes of the war. In the hope, probably, of inducing Nero to follow him and of gaining an opportunity of outmanoeuvring the Roman consul and attacking him on his march, Hannibal moved into Lucania, and then back into Apulia; he again marched down into Bruttium, and strengthened his army by a levy of recruits in that district. Nero followed him, but gave him no chance of assailing him at a disadvantage. Some partial encounters seem to have taken place; but the consul could not prevent Hannibal's junction with his Bruttian levies, nor could Hannibal gain an opportunity of surprising and crushing the consul.[[63]] Hannibal returned to his former headquarters at Canusium, and halted there in expectation of further tidings of his brother's movements. Nero also resumed his former position in observation of the Carthaginian army.
[!-- Note Anchor 63 --][Footnote 63: The annalists whom Livy copied spoke of Nero's gaining repeated victories over Hannibal, and killing and taking his men by tens of thousands. The falsehood of all this is self-evident. If Nero could thus always beat Hannibal, the Romans would not have been in such an agony of dread about Hasdrubal as all writers describe. Indeed, we have the express testimony of Polybius that the statements which we read in Livy of Marcellus, Nero, and others gaining victories over Hannibal in Italy must be all fabrications of Roman vanity. Polybius states that Hannibal was never defeated before the battle of Zama; and in another passage he mentions that after the defeats which Hannibal inflicted on the Romans in the early years of the war, they no longer dared face his army in a pitched battle on a fair field, and yet they resolutely maintained the war. He rightly explains this by referring to the superiority of Hannibal's cavalry, the arm which gained him all his victories. By keeping within fortified lines, or close to the sides of the mountains when Hannibal approached them, the Romans rendered his cavalry ineffective; and a glance at the geography of Italy will show how an army can traverse the greater part of that country without venturing far from the high grounds.]
Meanwhile, Hasdrubal had raised the siege of Placentia, and was advancing toward Ariminum on the Adriatic, and driving before him the Roman army under Porcius. Nor when the consul Livius had come up, and united the second and third armies of the North, could he make head against the invaders. The Romans still fell back before Hasdrubal beyond Ariminum, beyond the Metaurus, and as far as the little town of Sena, to the southeast of that river. Hasdrubal was not unmindful of the necessity of acting in concert with his brother. He sent messengers to Hannibal to announce his own line of march, and to propose that they should unite their armies in South Umbria and then wheel round against Rome. Those messengers traversed the greater part of Italy in safety, but, when close to the object of their mission, were captured by a Roman detachment; and Hasdrubal's letter, detailing his whole plan of the campaign, was laid, not in his brother's hands, but in those of the commander of the Roman armies of the South. Nero saw at once the full importance of the crisis. The two sons of Hamilcar were now within two hundred miles of each other, and if Rome were to be saved the brothers must never meet alive. Nero instantly ordered seven thousand picked men, a thousand being cavalry, to hold themselves in readiness for a secret expedition against one of Hannibal's garrisons, and as soon as night had set in he hurried forward on his bold enterprise; but he quickly left the southern road toward Lucania, and, wheeling round, pressed northward with the utmost rapidity toward Picenum. He had, during the preceding afternoon, sent messengers to Rome, who were to lay Hasdrubal's letters before the senate. There was a law forbidding a consul to make war or march his army beyond the limits of the province assigned to him; but in such an emergency, Nero did not wait for the permission of the senate to execute his project, but informed them that he was already on his march to join Livius against Hasdrubal. He advised them to send the two legions which formed the home garrison on to Narnia, so as to defend that pass of the Flaminian road against Hasdrubal, in case he should march upon Rome before the consular armies could attack him. They were to supply the place of these two legions at Rome by a levy en masse in the city, and by ordering up the reserve legion from Capua. These were his communications to the senate. He also sent horsemen forward along his line of march, with orders to the local authorities to bring stores of provisions and refreshment of every kind to the roadside, and to have relays of carriages ready for the conveyance of the wearied soldiers. Such were the precautions which he took for accelerating his march; and when he had advanced some little distance from his camp, he briefly informed his soldiers of the real object of their expedition. He told them that never was there a design more seemingly audacious and more really safe. He said he was leading them to a certain victory, for his colleague had an army large enough to balance the enemy already, so that their swords would decisively turn the scale. The very rumor that a fresh consul and a fresh army had come up, when heard on the battle-field—and he would take care that they should not be heard of before they were seen and felt—would settle the business. They would have all the credit of the victory and of having dealt the final decisive blow. He appealed to the enthusiastic reception which they already met with on their line of march as a proof and an omen of their good fortune. And, indeed, their whole path was amid the vows and prayers and praises of their countrymen. The entire population of the districts through which they passed flocked to the roadside to see and bless the deliverers of their country. Food, drink, and refreshments of every kind were eagerly pressed on their acceptance. Each peasant thought a favor was conferred on him if one of Nero's chosen band would accept aught at his hands. The soldiers caught the full spirit of their leader. Night and day they marched forward, taking their hurried meals in the ranks, and resting by relay in the wagons which the zeal of the country people provided, and which followed in the rear of the column.
Meanwhile, at Rome, the news of Nero's expedition had caused the greatest excitement and alarm. All men felt the full audacity of the enterprise, but hesitated what epithet to apply to it. It was evident that Nero's conduct would be judged of by the event, that most unfair criterion, as the Roman historian truly terms it. People reasoned on the perilous state in which Nero had left the rest of his army, without a general, and deprived of the core of its strength, in the vicinity of the terrible Hannibal. They speculated on how long it would take Hannibal to pursue and overtake Nero himself, and his expeditionary force. They talked over the former disasters of the war, and the fall of both the consuls of the last year. All these calamities had come on them while they had only one Carthaginian general and army to deal with in Italy. Now they had two Punic wars at a time. They had two Carthaginian armies, they had almost two Hannibals, in Italy. Hasdrubal was sprung from the same father; trained up in the same hostility to Rome; equally practised in battle against their legions; and, if the comparative speed and success with which he had crossed the Alps were a fair test, he was even a better general than his brother. With fear for their interpreter of every rumor, they exaggerated the strength of their enemy's forces in every quarter, and criticised and distrusted their own.
Fortunately for Rome, while she was thus a prey to terror and anxiety, her consul's nerves were stout and strong, and he resolutely urged on his march toward Sena, where his colleague Livius and the praetor Porcius were encamped, Hasdrubal's army being in position about half a mile to their north. Nero had sent couriers forward to apprise his colleague of his project and of his approach; and by the advice of Livius, Nero so timed his final march as to reach the camp at Sena by night. According to a previous arrangement, Nero's men were received silently into the tents of their comrades, each according to his rank. By these means there was no enlargement of the camp that could betray to Hasdrubal the accession of force which the Romans had received. This was considerable, as Nero's numbers had been increased on the march by the volunteers, who offered themselves in crowds, and from whom he selected the most promising men, and especially the veterans of former campaigns. A council of war was held on the morning after his arrival, in which some advised that time should be given for Nero's men to refresh themselves after the fatigue of such a march. But Nero vehemently opposed all delay. "The officer," said he, "who is for giving time to my men here to rest themselves is for giving time to Hannibal to attack my men, whom I have left in the camp in Apulia. He is for giving time to Hannibal and Hasdrubal to discover my march, and to manoeuvre for a junction with each other in Cisalpine Gaul at their leisure. We must fight instantly, while both the foe here and the foe in the South are ignorant of our movements. We must destroy this Hasdrubal, and I must be back in Apulia before Hannibal awakes from his torpor." Nero's advice prevailed. It was resolved to fight directly; and before the consuls and praetor left the tent of Livius, the red ensign, which was the signal to prepare for immediate action, was hoisted, and the Romans forthwith drew up in battle array outside the camp.
Hasdrubal had been anxious to bring Livius and Porcius to battle, though he had not judged it expedient to attack them in their lines. And now, on hearing that the Romans offered battle, he also drew up his men and advanced toward them. No spy or deserter had informed him of Nero's arrival, nor had he received any direct information that he had more than his old enemies to deal with. But as he rode forward to reconnoitre the Roman line, he thought that their numbers seemed to have increased, and that the armor of some of them was unusually dull and stained. He noticed, also, that the horses of some of the cavalry appeared to be rough and out of condition, as if they had just come from a succession of forced marches. So also, though, owing to the precaution of Livius, the Roman camp showed no change of size, it had not escaped the quick ear of the Carthaginian general that the trumpet which gave the signal to the Roman legions sounded that morning once oftener than usual, as if directing the troops of some additional superior officer. Hasdrubal, from his Spanish campaigns, was well acquainted with all the sounds and signals of Roman war, and from all that he heard and saw he felt convinced that both the Roman consuls were before him. In doubt and difficulty as to what might have taken place between the armies of the South, and probably hoping that Hannibal also was approaching, Hasdrubal determined to avoid an encounter with the combined Roman forces, and to endeavor to retreat upon Insubrian Gaul, where he would be in a friendly country, and could endeavor to reopen his communication with his brother. He therefore led his troops back into their camp; and as the Romans did not venture on an assault upon his intrenchments, and Hasdrubal did not choose to commence his retreat in their sight, the day passed away in inaction. At the first watch of the night Hasdrubal led his men silently out of their camp, and moved northward toward the Metaurus, in the hope of placing that river between himself and the Romans before his retreat was discovered. His guides betrayed him; and having purposely led him away from the part of the river that was fordable, they made their escape in the dark, and left Hasdrubal and his army wandering in confusion along the steep bank, and seeking in vain for a spot where the stream could be safely crossed. At last they halted; and when day dawned on them, Hasdrubal found that great numbers of his men, in their fatigue and impatience, had lost all discipline and subordination, and that many of his Gallic auxiliaries had got drunk, and were lying helpless in their quarters. The Roman cavalry was soon seen coming up in pursuit, followed at no great distance by the legions, which marched in readiness for an instant engagement. It was hopeless for Hasdrubal to think of continuing his retreat before them. The prospect of immediate battle might recall the disordered part of his troops to a sense of duty, and revive the instinct of discipline. He therefore ordered his men to prepare for action instantly, and made the best arrangement of them that the nature of the ground would permit.