Hannibal is primarily known for his efforts in the second Punic war, but was just as important in the role he played in the conquest of southeastern Spain in the 220s BCE.
Hannibal was the son of Hamilcar Barca, and started following his father on his campaigns already at the age of 9, when he set out to conquer Spain. From the time he was 18 until he was 25, he acted as a military leader under his brother-in-law, Hasdrubal, in connection with the extension and consolidation of Carthaginian power in Spain.
With Hasdrubal's death in 221, Hannibal was elected new commander-in-chief. Under his control, the Carthaginians made large territorial advances, but with the conquest of Saguntum (Sagunto, Spain) in 218, he clashed with the Roman army. The Romans claimed that this was a break of an existing treaty between Rome and Carthage, and demanded Hannibal surrender to them. With the refusal of Carthage, the second Punic war started.
Hannibal set out on his legendary march from New Carthage (Cartagena, Spain) in 218 BCE. At first he crossed the Pyrenees; later he traversed the Alps through narrow and dangerous passes of up to more than 2000 metres above sea level. The exact crossing is not known, but it was probably somewhere between the Little St. Bernard and Mt. Geveva passes.
Even if many were lost to his army during this march, because of snowstorms, landslides, and attacks from hostile local tribes, he managed to recruit new personnel along the route. It is believed that he lost about 15,000 men on the whole campaign.
Hannibal soon suppressed local peoples in northern Italy. The first people were the Taurini, then the Ligurian and Celtic tribes north of the Po river. Hannibal's victories at Ticinus and Trebia in 218, and at Trasimene lake in 217 demonstrated the inadequacy of the Roman army. Soon after, he invaded Roman territory, but never came closer than 150 km to Rome, before he temporarily settled in Campania.
Hannibal faced the Roman general, Quintus Fabius, whose strategy was to avoid decisive battles. Yet he managed to keep Hannibal away from Rome. As years passed, Hannibal's morale and resources were strained, while Rome rebuilt its military strength. After 216 Hannibal established himself in Cannae (now Barletta), 400 km east of Rome. From this vantage point, Hannibal enjoyed a period when he could count some of his most impressive victories.
After some time the Carthaginian government stopped sending reinforcements. When Hannibal finally attacked Rome in 211, a battle which ended in failure, many of Hannibal's allies deserted him. In 207 his brother Hasdrubal tried to come to rescue Hannibal's, but he was stopped by the Roman army.
In 203 Hannibal was summoned back to Carthage. Back on home soil, Carthage faced Rome's forces on many fronts, but at the decisive battle at Zama (near today's Maktar, Tunisia (see travel guide) in 202, Hannibal's troops fled, because the army facing him was too strong. This defeat brought the final end of the warfare, and Rome left as the stronger force.
Peace was agreed upon in 201, according to Hannibal's own peace terms. In 196 BCE, Hannibal became shophet, or chief magistrate, of Carthage, and he took charge over Carthage's economy in order to bring it back to the stage from which struggle against Rome could be resumed.
The Romans reacted to his obvious ambitions by sacking him from Carthage. Hannibal fled to Syria, to the court of Antiochus 3. Antiochus fought together with Hannibal against Rome, but when Antiochus was defeated in 190, Hannibal fled to Crete, and later Bithynia (now Izmit) in northern Asia Minor. The story repeated itself, warfare together with new allies against Rome resulted in defeat, but this time Hannibal committed suicide by poison instead of surrendering.