After allowing his men to recruit in the villages of the friendly Insubres, he overcame the Taurini, besieging and taking Turin, and forced the Ligurian and Celtic tribes on the Upper Po to serve in his army. At the Ticinus, a stream which enters the Po near Pavia, he encountered the Romans under Scipio, the father of Scipio Africanus. The cavalry of both armies joined battle, Hannibal's Numidian horse proved their superiority, and Scipio fell back beyond the Po. The Carthaginians crossed the river, and the first great battle of the campaign was fought in the plain of the Trebia. Placing Mago in ambush with 2,000 men, Hannibal enticed the Romans across the stream. His light troops retired before the legionaries, and as Scipio was pressing on to fancied victory he was taken in flank by the terrible Numidian horse, Mago came down in the rear, and the 40,000 men of the consular army were either cut to pieces or scattered in flight. Wintering in the valley of the Po, in the early spring Hannibal crossed the Apennines and pushed through a region of lakes, flooded by the melting of the snow, to Fæsulæ. The beasts of burden perished in vast numbers amid the morasses; the Gauls, disheartened by the perils of the journey, had to be driven forward by Mago's horsemen, and the general lost an eye. Quitting Fæsulæ, Hannibal wasted Etruria with fire and sword, and marched toward Rome, leaving behind him two consular, armies of 60,000 men. He awaited the consul Flaminius by the Lake Trasimene, where the hills, retiring in a semicircle from the shore, enclose a plain entered by two narrow passes. Concealing the main body of his army amid the hills, he placed his Numidians in ambush at the pass by which the Romans must enter; while he stationed part of his infantry in a conspicuous position near the other defile. The Romans pushed into the valley; the pass in their rear was secured by the Carthaginians who had lain in ambush; Hannibal's men charged from the heights, and the army of Flaminius was annihilated. Six thousand infantry cut their way through the farther pass, but these were overtaken by the horse under Maherbal and forced to yield on the following day.

After recruiting his men in the champaign country of Picenum, where the Numidian horses, we are told, were groomed with old Italian wine, Hannibal marched through Apulia and ravaged Campania, dogged by the dictator Quintus Fabius Maximus, whom he vainly endeavored to entice into an engagement. He wintered at Gerontium, and in the spring took up a position at Cannæ, on the Aufidus. A Roman army of 80,000 men, under the consuls L. Æmilius Paulus and P. Terentius Varro, marched against him. Hannibal flung his troops (he had but 30,000) into a space enclosed on the rear and wings by a loop of the river. He placed his Spanish infantry in the centre, with the African foot on either flank. His Numidian horse, now reduced to 2,000 men, he posted on the right wing; while Hasdrubal, with 8,000 heavy cavalry, was opposed to the Roman cavalry on the left. The legionaries pressed into the loop, and Hannibal drew back his centre before them. Hasdrubal, on the left, broke the Roman cavalry, swept round to the left wing of the Romans, drove the second detachment of Roman horse into flight, and then came thundering in the rear of the legionaries. The Libyans, who had by the general's orders fallen back as the Romans pressed after the retiring Spanish infantry, now closed on the enemy's flanks. Packed together so closely that they could not use their weapons, assailed in front, flank, and rear, the legionaries were hewn down through eight hours of carnage, till 50,000 lay dead on the field. The battle became a butchery. Nearly 20,000 men were taken prisoners. The consul Paulus, the pro-consul Servilius, the master of the horse Minucius, 21 military tribunes, and 60 senators lay amid the slain. On his side Hannibal lost but 5,700 men. "Send me on with the horse, general," said Maherbal, "and in five days thou shalt sup in the Capitol."

But the general was wiser than the fiery captain of the horse. It has been common to censure Hannibal for neglecting to march on Rome after the battle of Cannæ. But his dazzling triumph did not for a moment unsettle his clear judgment. He knew that his forces were unequal to the task of storming a walled city garrisoned by a population of fighting men. An attack which he had made on Spoletium had proved the inadequacy of the small Carthaginian army to, carry a strongly fortified town. Had he followed the advice of Maherbal, he would in all likelihood have dashed his army to pieces against the walls of Rome. His aim was to destroy the common oppressor by raising the Italian allies against her; and the hope was partly justified by the revolt of Lucania and Bruttium, Samnium and Apulia. The soundness of judgment, the patience and self-control which he evinced in this hour of intoxicating success, are hardly less marvellous than the genius by which the success had been won. After the battle of Cannæ the character of the war changes. Hitherto Hannibal had swept everything before him. Rivers and mountains and morasses had been powerless to thwart his progress. Army after army, vastly superior in numbers and composed of the best fighting men the ancient world ever saw, had come against him to be broken, scattered, and destroyed. His career through Italy had been, in the words of Horace, as the rush of the flames through a forest of pines. But after Cannæ the tide turned. His niggardly, short-sighted countrymen denied him the support without which success was impossible. As his veterans were lost to him he bad no means of filling their places, while the Romans could put army after army into the field. But through the long years during which he maintained a hopeless struggle in Italy he was never defeated. Nor did one of his veterans desert him; never was there a murmur of disaffection in his camp. It has been well said that his victories over his motley followers were hardly less wonderful than his victories over nature and over Rome.

Hannibal spent the winter of 216-215 B.C. at Capua, where his men are said to have been demoralized by luxurious living. When he again took the field the Romans wisely avoided a pitched battle, though the Carthaginians overran Italy, capturing Locri, Thurii, Metapontum, Tarentum, and other towns. In 211 B.C. he marched on Rome, rode up to the Colline gate, and, it is said, flung his spear over the walls. But the fall of Capua smote the Italian allies with dismay, and ruined his hopes of recruiting his ever-diminishing forces from their ranks. In 210 B.C. he overcame the prætor Fulvius at Herdonea, and in the following year gained two battles in Apulia. Thereafter, he fell upon the consuls Crispinus and Marcellus, both of whom were slain and their forces routed, while he almost annihilated the Roman army which was besieging Locri. In 207 B.C. his brother Hasdrubal marched from Spain to his aid, but was surprised, defeated, and slain at the Metaurus by the consul Nero. By the barbarous commands of Nero, Hasdrubal's head was flung into the camp of Hannibal, who had been till then in ignorance of his brother's doom. The battle of the Metaurus sealed the fate of "the lion's brood"—of the great house of Hamilcar. But for four years Hannibal stood at bay in the hill-country of Bruttium, defying with his thinned army every general who was sent against him, till in 202 B.C., after an absence of fifteen years, he was recalled to Africa to repel the Roman invasion. In the same year he met Scipio at Zama; his raw levies fled, and in part went over to the enemy; his veterans were cut to pieces where they stood, and Carthage was at the mercy of Rome. So ended the Second Punic War—the war, as Arnold so truly said, of a man with a nation, and the war which is perhaps the most wonderful in all history. Three hundred thousand Italians had fallen, and three hundred towns had been destroyed in the struggle.

Peace being made, Hannibal turned his genius to political toils. He amended the constitution, cut down the power of the ignoble oligarchy, checked corruption, and placed the city's finances on a sounder footing. The enemies whom he made by his reforms denounced him to the Romans, and the Romans demanded that he should be surrendered into their hands. Setting out as a voluntary exile, Hannibal visited Tyre, the mother-city of Carthage, and then betook himself to the court of Antiochus, at Ephesus. He was well received by the king, who nevertheless rejected his advice to carry the war with Rome into Italy. On the conclusion of peace, to avoid being given up to the Romans, he repaired to Prusias, king of Bithynia, for whom he gained a naval victory over the king of Pergamus. The Romans again demanding that he should be surrendered, he baffled his enemies by taking poison, which, we are told, he carried about with him in a ring, and died at Lybyssa about the year 183 B.C.

In judging of the character and achievements of Hannibal, it must never be forgotten, that for all we know of him, we are indebted to his implacable enemies. No Carthaginian record of that astounding career has come down to us. The Romans did all that unscrupulous malignity can, to blacken the fame and belittle the deeds of the most terrible of their foes. Yet, though calumny has done its' bitterest against him, Hannibal not only dazzles the imagination, but takes captive the heart. He stands out as the incarnation of magnanimity and patriotism and self-sacrificing heroism, no less than of incomparable military genius. Napoleon, the only general who could plausibly challenge the Carthaginian's supremacy, had throughout the greater part of his career an immense superiority to his adversaries in the quality of the forces which he wielded. He had the enthusiasm of the Revolution behind him, and he was unhampered by authorities at home. Hannibal, on the contrary, saw his plans thwarted and finally wrecked by the sordid merchant-nobles of the city he strove so hard to save. He had not, like Alexander, to lead picked troops against effeminate Asiatics. He had to mould his little army out of raw and barbarous levies. He had no reinforcements to fall back on. With a motley army of Libyans, Gauls, and Spaniards he had to encounter a nation in arms—a nation of the stoutest and most highly trained warriors of ancient times. There is not in all history so wonderful an example of what a single man of genius may achieve against the most tremendous odds, as the story of the Phœnician hero—the greatest captain that the world has seen.