All three were apt pupils.
When Hannibal was eighteen, Hamilcar was killed in a battle with some of the native tribes who had refused to submit to the sway of Carthage. In spite of the hatred that he cherished for everything Roman, he had earned the undying respect of the noblest among them. 'No king was equal to Hamilcar Barca,' writes Cato the elder, and the words of Livy the historian about Hannibal might also be applied to his father.
'Never was a genius more fitted to obey or to command. His body could not be exhausted nor his mind subdued by toil, and he ate and drank only what he needed.' He had failed in his aim, but, dying, he left it as a heritage to his son, who, on the point of victory, was to fail also.
Under Hamilcar's son-in-law, Hasdrubal, the work of training the army, encouraging agriculture, and fostering trade was carried on as before. It was not long before Hasdrubal made his young brother-in-law commander of the cavalry, and often sought counsel from him in any perplexity. Hannibal was much beloved, too, by his soldiers of all nations, and to the end they clung to him through good and ill. He gave back their devotion by constant care for their comfort—very rare in those days—seeing that they were fed and warmed before entering on a hard day's fighting, and arranging that they had proper time for rest. To the Iberians he was bound by special ties, for before he quitted Spain for his death-struggle with Rome he married a Spanish princess, little thinking, when he started northwards in May 218 b.c., that he was leaving her and her infant son behind him for ever.
All this time Rome had been growing both in her influence and her dominions, when for a while her very existence was threatened by the sudden invasion of seventy thousand Gauls, who poured in from the north. They were defeated in a hard-fought battle and beaten back, but the struggle with the barbarians was long and fierce, and Rome remained exhausted. Her attention was occupied with measures needful for her own defence and in raising both men and money, and except for warning the Carthaginians not to cross the Ebro, she left them for a time pretty much to themselves, thinking vainly that, as long as her navy gave her command of the sea, she had no need to trouble herself about affairs in Spain or Africa. Indeed, after the severe strain of the Gallic war, the Roman senate thought that they were in so little danger either from Carthage or from Greece that their troops might take a sorely needed rest, and the army was disbanded.
This was Hannibal's chance, and with the siege and fall of the Spanish town of Saguntum in 218 b.c. began the second Punic war.
For years the young general had been secretly brooding over his plans, and had prepared friends for himself all along the difficult way his army would have to march. Unknown to Rome, he had received promises of help from most of the tribes in what is now the province of Catalonia, from Philip of Macedon, ruler in the kingdom of Alexander the Great, and from some of the Gauls near the Rhone and along the valley of the Po. Many of these proved broken reeds at the time of trial, when their help was most needed, and even turned into enemies, and Hannibal was too wise not to have foreseen that this might happen. Still, for the moment all seemed going as he wished; war was declared, and Rome made ready her fleet for the attack by sea which she felt was certain to follow.