=98.= At nine years of age he had accompanied his father into Spain, and before the altar of his country’s gods had taken a solemn oath of eternal and unrelenting enmity to Rome. The oath of the child had not been forgotten by the youth. At the age of eighteen he fought by his father’s side in the battle where Hamilcar was slain; and during the following eight years of Hasdrubal’s administration, that general intrusted his young brother-in-law with the command of most of his military enterprises. Upon the death of Hasdrubal, the army by acclamation placed Hannibal at its head, and the government at home neither could nor would annul the appointment. Having confirmed his power in Spain by two years’ war against the native tribes, Hannibal deliberately sought the quarrel with Rome to which he had devoted his life. The Greek city of Saguntum had placed itself under the protection of Rome. It was attacked by Hannibal, and taken after an obstinate defense of eight months. The Romans sent to Carthage to demand the surrender of the young general for this breach of the treaty. The reply was a declaration of war. =99.= Leaving his brother Hasdrubal in charge of Spain, Hannibal prepared for a bolder movement than the Romans had foreseen. He knew that the great mountain-barrier of the Alps had already often been traversed by the Gauls, and he relied upon finding able guides among this people, who were mostly friendly to Carthage. He resolved, therefore, on the hitherto unprecedented feat of leading an army from Spain into Italy by land. Having offered, during the winter, solemn sacrifices and prayers for success, at the distant shrine of the Tyrian Hercules at Gades, he set forth from Carthagena, in the spring of 218 B. C., with an army of 90,000 foot, 12,000 horse, and a considerable number of elephants. The Spanish tribes between the Ebro and the Pyrenees were yet to be overcome. They resisted bravely, but were subdued, and a force of 11,000 men was left to hold them in subjection. =100.= Having passed the Pyrenees, Hannibal advanced through friendly tribes of Gauls to the Rhone, which he crossed near the modern town of Orange, gaining an advance of three days upon the army of Scipio, the consul, who had intended to stop him. The passage of the Alps, with such a force, was one of the greatest military achievements of ancient times. The higher mountains were already obstructed by the snows of early autumn; hostile tribes contested his passage in narrow and dangerous defiles; and in two fierce battles, the army of Hannibal narrowly escaped total destruction. When, after fifteen days of toilsome and dangerous marching, he emerged into the plain of the Po, it was with scarcely more than one-fourth of the great army which had accompanied him from Carthagena.