Then at the age of 25, Hannibal was elected leader in Spain by the army.8.
Hannibal now went about Spain and used a mixed tactic of Hamlicar's military might and Hasdrubal's diplomatic skill. He subjugated many Celtiberian tribes, and married a Celtiberian princess to establish a rightful claim as overlord of Spain. Then he turned his attention to a Greek port city of Saguntum, which had made itself a "friend of Rome" and therefore Rome was supposedly obliged to defend it. Saguntum being in the middle of the Carthaginian holding was not a help here, and Hannibal saw this as an opportunity to pick a fight with Rome. He laid siege to Saguntum in 219 BCE to force the Romans to decide whether or not to defend this ally. They did not send any help, and Saguntum fell to Hannibal. Now while debate raged in Rome for declarations of war, Hannibal did not waste time bickering.9 He packed up 40,000 troops in the early spring of 218 to make a land march into Italy. He left his brother Hasdrubal Barca in charge of Spain, while along the way he left his brother Mago Barca with 10,000 of the 40,000 to control the Gallic tribes of the region.10.
Hannibal had perceived from the results of the First Punic War that to defeat Rome was to defeat Rome itself, not its allies or colonies. And since Romans had mastery of the sea by this point in time, the only possible discourse by which to transport an army to Italy from Spain was over the Alps. After several battles with hostile Gallic tribes of the mountainous region and many engineering feats enabling such an army with horse and elephants to pass, Hannibal .
3.
emerged from the Alps into Northern Italy late in November of 218. Now we see the true genius of Hannibal: defeating the illustrious Roman legions with hordes of mercenaries and loose allies.
At this point, one must realize that the Carthaginian army was much different than the organized Roman legion.
