Battle of the Trebia (218 BC)

Outbreak of the Second Punic War

After Carthage had been defeated by the Romans in the First Punic War, but had subsequently expanded its power again, a renewed conflict with Rome was inevitable. The Greek historian Polybios, who reflects the Roman view, saw the expansion of Punic rule in Hispania as the establishment of a power base for a war of revenge against the Romans:

"For as soon as Hamilcar, with whose personal resentment his and all the Carthaginians' indignation at this rape was united, had fought down the rebellious mercenaries and secured peace and tranquillity for his native city, his initiative was immediately directed to Iberia, in order to gain there the means of war against the Romans. And this now is to be regarded as the third cause [of the later war], I mean the successes of Carthaginian policy in Iberia. For, confident of the power they had gained there, they proceeded confidently to war."

That Carthage actually wanted war at this time, however, is unlikely. The Ebro Treaty between Hasdrubal and Rome in 226 BC, which established the Ebro as the border between Rome and Carthage, disproves Polybios' view: it was not Carthage but Rome that was looking for a pretext to declare war. When the barquid Hannibal captured the city of Sagunt south of the Ebro in 219, with which the Romans had shortly before allied themselves in violation of the agreement, the Roman Senate changed its behavior and threatened Carthage with war if the latter did not immediately hand over Hannibal. The Romans wanted to act before Carthage became more powerful again, and since they had just subdued the Gauls in the Po Valley, the timing seemed opportune. So in 219 BC they made an unacceptable offer in the Carthaginian council: 'Then the Roman [Quintus Fabius], gathering his toga into a hollow, said: 'Here we bring you war and peace; take what you will!' To these words they no less defiantly replied with clamour that he might give them what he wanted. And when, on the other hand, pouring out the hollow, he declared that he was giving them war, they all answered that they accepted it, and would wage it with the very courage with which they accepted it."

Hannibal's train through the Alps

At the outbreak of the war, Hannibal had about 90,000 foot soldiers and 12,000 horsemen at his disposal. He decided to pre-empt the Romans, who were preparing an invasion of Africa, by going on the offensive himself. Since the Roman fleet had controlled the sea since 241, Hannibal had only the land route available to attack Rome in Italy. To defend the conquered territories in Hispania, he left 10,000 infantry under Hanno in Hispania and sent another 10,000 to the threatened African homeland. Furthermore, he carried 37 war elephants with him.

Historians are still not in agreement about the route he took, but it is assumed that he first went upstream the Rhodanus (Rhône) and later the Isara (Isère). According to Polybios, he probably crossed the Alps via the Col de Clapier and descended into what is now Italy at the onset of winter. Almost six months after he left Carthago Nova, some 38,000 foot soldiers, 8,000 horsemen, all 37 elephants, plus 12,000 Libyans and 8,000 Spanish foot soldiers reached the Po Valley in November. The reasons for the land route were, on the one hand, the dangers of a sea voyage, especially as the Roman fleet was far superior to Carthage's fleet after the First Punic War, as already mentioned, and, on the other hand, the element of surprise. Moreover, Hannibal tried with success to win over several Gallic tribes. But also on the land way about 9,000 Punic perished.

Roman tactics and the Battle of Ticinus

→Main article Battle of Ticinus

Roman tactics envisaged a double attack on Carthage-occupied Hispania as well as on the Carthaginian heartland on the North African coast. The attack on Hispania was led by Publius Cornelius Scipio (consul 218 BC), who was already on his way to Spain with the fleet when he learned in Massilia of Hannibal's crossing of the Rhône. But despite his scouts, Scipio did not succeed in confronting Hannibal before the Alps, whereupon he returned to Italy to confront the Carthaginian in the Po Valley. The attack on North Africa was led by Tiberius Sempronius Longus, who, upon receiving Scipio's message, broke off his preparations in Sicily and turned to the theater of war in northern Italy.

Of the two consuls, Scipio was the first to reach the Po, marching towards Hannibal with a force of about 2,500 foot soldiers and 1,500 mounted men, and setting up camp near the river Ticinus. A chance meeting of scouting parties thus developed into the first battle in November 218 BC. When the Punic units attacked, the Roman spearmen fled and the Carthaginian cavalry surrounded the remaining legionaries, who were completely routed. Scipio was severely wounded in the engagement and was reportedly only saved by a heroic intervention by his son.

After the defeat, Scipio wanted to avoid Hannibal as much as possible and wait for further reinforcements from Rome. But Sempronius, who had rushed from Sicily to help, demanded a military decision before the end of December 218 BC.

Initial situation

The consul had taken up a position near the fortress of Placentia, but, Gallic formations having been sighted, was compelled to abandon it, and established himself on the hills behind the Trebia. The Carthaginian vanguard, composed mainly of Numidian horsemen, found only the camp abandoned, wasting time in plundering rather than in pursuit of the Romans.

These had now taken up their initial positions, thus hindering Hannibal's onward march and forcing him to camp on the other side of the river. Sempronius already lulled himself into security, since his camp seemed protected by the Apennines on the left wing, the Po and the fortress of Placentia on the right wing, and the Trebia promised him an advantage in Hannibal's attack in this particularly cold winter. The consul's army, meanwhile, amounted to about 36,000 Roman infantry, 3,000 Gallic allies, and 4,000 equites auxiliares (light cavalry auxiliaries). Scipio urged Sempronius to wait from his sickbed, but the consul now had sole command as a result of Scipio's wounding and, aware that his term was expiring in a few months, pressed for a decision.

Hannibal, well informed by espionage, recognized this advantage, laid waste all the villages that remained loyal to the Romans, and gave them victory in a cavalry skirmish. His army strength was about 20,000 foot soldiers (three-fifths Libyans, two-fifths Spaniards) and about 6,000 experienced cavalrymen.

The day of the battle

On the rainy and cold morning of December 18, Hannibal's cavalry drew those of the Romans to their side of the river and engaged them in a skirmish. The impatient consul saw his cavalry in danger and dispatched his main army, still tired and deprived of its morning meal, to fight. Hannibal, on the other hand, had his soldiers rubbed with grease and built campfires. In addition, he stationed his brother Mago with 1,000 Gallic horsemen and as many infantrymen well camouflaged by the dense forest on his right.

Meanwhile the hungry, fatigued, and drenched legionaries crossed the icy Trebia with difficulty. Immediately the battle developed, the Carthaginian having his elephants and cavalry attack the wings of the Romans, where their last mounted men were. These were completely routed and the Carthaginian horsemen now put the legionaries to the sword. These knew that retreat through the Trebia meant their certain death and fought back bitterly. But now Hannibal gave Mago the order to attack and had his troops attack the left side of the Romans from ambush. The wings of the Romans and the last links of the centre were dissolved by this attack and panic set in. Nevertheless, the most able legionaries managed to cut a swathe through the Gallic mercenary formations in the Carthaginian left, allowing some 10,000 Romans to escape to Placentia.

Ancient historians estimate the Roman losses at about 20,000 fighters, among them many nobles and almost the entire cavalry. Nevertheless, the victory also cost the Carthaginians dearly. They lost not only the Gallic mercenary troops, but also many of the older and more experienced soldiers who succumbed to their injuries or fell victim to the harsh cold. At the same time, disease ravaged all but one of the war elephants on which Hannibal rode to Arretium (Arezzo) in the spring of 217 BC.