But how could Italy be attacked? He might succeed in reaching the peninsula by sea or by land; but if the project was to be no mere desperate adventure, but a military expedition with a strategic aim, a nearer basis for its operations was requisite than Spain or Africa. Hannibal could not rely for support on a fleet and a fortified harbour, for Rome was now mistress of the sea. As little did the territory of the Italian confederacy present any tenable basis. If in very different times, and in spite of Hellenic sympathies, it had withstood the shock of Pyrrhus, it was not to be expected that it would now fall to pieces on the appearance of the Phoenician general; an invading army would without doubt be crushed between the network of Roman fortresses and the firmly-consolidated confederacy. The land of the Ligurians and Celts alone could be to Hannibal, what Poland was to Napoleon in his very similar Russian campaigns. These tribes still smarting under their scarcely ended struggle for independence, alien in race from the Italians, and feeling their very existence endangered by the chain of Roman fortresses and highways whose first coils were even now being fastened around them, could not but recognize their deliverers in the Phoenician army (which numbered in its ranks numerous Spanish Celts), and would serve as a first support for it to fall back upon - a source whence it might draw supplies and recruits. Already formal treaties were concluded with the Boii and the Insubres, by which they bound themselves to send guides to meet the Carthaginian army, to procure for it a good reception from the cognate tribes and supplies along its route, and to rise against the Romans as soon as it should set foot on Italian ground. In fine, the relations of Rome with the east led the Carthaginians to this same quarter. Macedonia, which by the victory of Sellasia had re-established its sovereignty in the Peloponnesus, was in strained relations with Rome; Demetrius of Pharos, who had exchanged the Roman alliance for that of Macedonia and had been dispossessed by the Romans, lived as an exile at the Macedonian court, and the latter had refused the demand which the Romans made for his surrender. If it was possible to combine the armies from the Guadalquivir and the Karasu anywhere against the common foe, it could only be done on the Po. Thus everything directed Hannibal to Northern Italy; and that the eyes of his father had already been turned to that quarter, is shown by the reconnoitring party of Carthaginians, whom the Romans to their great surprise encountered in Liguria in 524.
The reason for Hannibal's preference of the land route to that by sea is less obvious; for that neither the maritime supremacy of the Romans nor their league with Massilia could have prevented a landing at Genoa, is evident, and was shown by the sequel. Our authorities fail to furnish us with several of the elements, on which a satisfactory answer to this question would depend, and which cannot be supplied by conjecture. Hannibal had to choose between two evils. Instead of exposing himself to the unknown and less calculable contingencies of a sea voyage and of naval war, it must have seemed to him the better course to accept the assurances, which beyond doubt were seriously meant, of the Boii and Insubres, and the more so that, even if the army should land at Genoa, it would still have mountains to cross; he could hardly know exactly, how much smaller are the difficulties presented by the Apennines at Genoa than by the main chain of the Alps. At any rate the route which he took was the primitive Celtic route, by which many much larger hordes had crossed the Alps: the ally and deliverer of the Celtic nation might without temerity venture to traverse it.
So Hannibal collected the troops, destined for the grand army, in Cartagena at the beginning of the favourable season; there were 90,000 infantry and 12,000 cavalry, of whom about two-thirds were Africans and a third Spaniards. The 37 elephants which they took with them were probably destined rather to make an impression on the Gauls than for serious warfare. Hannibal's infantry no longer needed, like that led by Xanthippus, to shelter itself behind a screen of elephants, and the general had too much sagacity to employ otherwise than sparingly and with caution that two-edged weapon, which had as often occasioned the defeat of its own as of the enemy's army. With this force the general set out in the spring of 536 from Cartagena towards the Ebro. He so far informed his soldiers as to the measures which he had taken, particularly as to the connections he had entered into with the Celts and the resources and object of the expedition, that even the common soldier, whose military instincts lengthened war had developed, felt the clear perception and the steady hand of his leader, and followed him with implicit confidence to the unknown and distant land; and the fervid address, in which he laid before them the position of their country and the demands of the Romans, the slavery certainly reserved for their dear native land, and the disgrace of the imputation that they could surrender their beloved general and his staff, kindled a soldierly and patriotic ardour in the hearts of all.
The Roman state was in a plight, such as may occur even in firmly-established and sagacious aristocracies. The Romans knew doubtless what they wished to accomplish, and they took various steps; but nothing was done rightly or at the right time. They might long ago have been masters of the gates of the Alps and have settled matters with the Celts; the latter were still formidable, and the former were open. They might either have had friendship, with Carthage, had they honourably kept the peace of 513, or, had they not been disposed for peace, they might long ago have conquered Cartilage: the peace was practically broken by the seizure of Sardinia, and they allowed the power of Carthage to recover itself undisturbed for twenty years. There was no great difficulty in maintaining peace with Macedonia; but they had forfeited her friendship for a trifling gain. There must have been a lack of some leading statesman to take a connected and commanding view of the position of affairs; on all hands either too little was done, or too much. Now the war began at a time and at a place which they had allowed the enemy to determine; and, with all their well-founded conviction of military superiority, they were perplexed as to the object to be aimed at and the course to be followed in their first operations. They had at their disposal more than half a million of serviceable soldiers; the Roman cavalry alone was less good, and relatively less numerous, than the Carthaginian, the former constituting about a tenth, the latter an eighth, of the whole number of troops taking the field. None of the states affected by the war had any fleet corresponding to the Roman fleet of 220 quinqueremes, which had just returned from the Adriatic to the western sea. The natural and proper application of this crushing superiority of force was self-evident. It had been long settled that the war ought to be opened with a landing in Africa. The subsequent turn taken by events had compelled the Romans to embrace in their scheme of the war a simultaneous landing in Spain, chiefly to prevent the Spanish army from appearing before the walls of Carthage. In accordance with this plan they ought above all, when the war had been practically opened by Hannibal's attack on Saguntum in the beginning of 535, to have thrown a Roman army into Spain before the town fell; but they neglected the dictates of interest no less than of honour. For eight months Saguntum held out in vain: when the town passed into other hands, Rome had not even equipped her armament for landing in Spain. The country, however, between the Ebro and the Pyrenees was still free, and its tribes were not only the natural allies of the Romans, but had also, like the Saguntines, received from Roman emissaries promises of speedy assistance. Catalonia may be reached by sea from Italy in not much longer time than from Cartagena by and: had the Romans started, like the Phoenicians, in April, after the formal declaration of war that had taken place in the interval, Hannibal might have encountered the Roman legions on the line of the Ebro.