The Battle of Trebia

  By Alexander J. Knights, 21 March 2007; Revised
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With the outbreak of war in 218 BC, feelings between Rome and Carthage were an indication of the severe distrust and hostility between the two Mediterranean powers. On the footsteps of the frozen Alps, two forces would clash in an almighty battle, after which Hannibal would enforce his presence in , mercilessly and ruthlessly.

The situation was complicated, though Carthage had rights to everything south of the Ebro River, Iberia, Rome was disgusted at the siege of their allies in the Greek settlement of Saguntum. Delegates were immediately sent to Carthage, in order to negotiate the crisis. Carthage ended up handing the decision over to the Roman delegation, who opted for war – and war it was.
After taking Saguntum by force August, Hannibal set off through Northern Iberia, affirming his presence along the way. He left his brother Hasdrubal with a garrison, as well as discarding his unfit-for-battle troops as garrisons for the regions north of the River Ebro. At this stage his army consisted of 30-40,000 infantry, mainly comprised of Celtiberians, Iberians and his elite Libyan Spearmen. Hannibal also left with 10,000 cavalry, both his eclectic Numidians and a variety of Carthaginian and Spanish Heavy Cavalry.

Whilst Hannibal was making his move, Rome was raising its legions, and preparing for a naval assault. They sent Gnaeus Scipio to , as well as Publius Scipio shortly after. Hannibal continued to move north, subduing ambushes and skirmishes by hostile Gallic tribes along the way, but also gaining the support of many, enabling him to repopulate his ever diminishing army. By the time Hannibal had reached the Alps, he had 38,000 infantry and 8,000 cavalry[1], and some remaining war elephants.By gaining further support from Latins and Cisalpine Gauls, he managed to boost his numbers but was still left with half the numbers he originally departed with. After the long and costly crossing of the Alps and Rhone River (where he encountered fierce Gaulish resistance), Hannibal and his army set foot on the plains of Italia. Rome’s scouts rapidly alerted them of the strategic surprise sprung upon them by Hannibal, and Publius Scipio was immediately called back to .

Hannibal’s first Roman engagement occurred at the River Ticinus, where his cavalry contingent destroyed the consular cavalry force of Publius. Consul Titus Sempronius Longus was called from Sicily to face the threat from the Carthaginian and he reacted swiftly, marching his army up to the Apennines and into Northern Italy in just forty days. Titus was eager for battle, and battle was what he would get.The Alpine foothills were still frozen even in December, and nearby Hannibal’s camp, the River Trebia was near freezing. Longus set up camp on the opposite side of the river to Hannibal. On the eve of 17th December 218 BC Hannibal ordered his troops to rest, but rise early.

Before sunrise, his troops stirred and awoke. They were promptly ordered to eat breakfast and put oil over their skin to keep them warm in the ordeal to come. A contingent of elite Numidian horsemen was sent to provoke the slumbering Romans. As they crossed the freezing river, Hannibal’s troops were getting into formation. Hannibal had commanded his brother Mago to take 2,000 Heavy Cavalry (plus a selection of offensive infantry) to lay in ambush adjacent to his main battle line, and hidden. The Numidian cavalry approached the Roman camp and harassed them with javelins and slander. This provoked the impetuous Sempronius into rash action. Without allowing time for breakfast, or even proper organisation, he headed his army into the freezing River Trebia. By now, Hannibal’s lines were complete. In the center were his Gaulish, Ligurian and Celtiberian infantry, and flanking them on either side were the prized Libyans and Iberians. All in all, 20,000 infantry[2], with 8,000 cavalry evenly split on the sides of Hannibal’s thin battlefront.

His army were well-fed, organised and most importantly, warm. Sempronius traversed the icy Trebia with his 16,000 Legionnaires and 20,000 allied troops (debatable) on their flanks. 2,000 Equestrians took up either side of the Roman battle columns. The Carthaginian javelineers and slingers picked off the undefended Romans crossing the river, reducing the forces significantly, but having to fall back as they were overwhelmed.
The approaching Romans must have been petrified at the imposing sight of Hannibal’s vicious multicultural army, but the huge beasts that he had looming among the forces would have been a monumental break in morale for the already freezing and hungry Romans. Hannibal’s remaining elephants trumpeted as the Roman advance continued. By the time the whole army had crossed, they armies engaged. It was snowing, but Hannibal’s men were kept warm by the coating of oil covering their bodies. This allowed for a heartier fight, and the Libyan and Iberian flanks were rapidly eating into the allied Latin lines. On the other hand, the Gallic centre was struggling against the sheer force of the professional heavy legionnaires.
As if it were on cue, like a ghostly whisper in the dark night, Mago and his cavalry charged into the rear. The cavalry sanctioned on the main battle flanks had repelled the Roman equestrians, and had now conglomerated into a mass force of cavalry. The Roman army was now sure of defeat, but was not going to give up. While Mago’s charge had annihilated the Latin allies, it had not greatly affected the Roman centre.

By now the skirmishes and cavalry had averted their attention from the allies to the legionnaire centre. The Roman heavy infantry had made a gallant effort, managing to break the Carthaginian centre. They managed to flee to the nearby town of Placentia. Hannibal had won his first major engagement on Italian territory. The role of Hannibal’s elephants at Trebia is questionable, and while some believe that they were an integral part of the victory. The general consensus is, however, that the elephants played a minor role in the victory, with most succumbing to the cold and wounds. By the end of the battle, only a few remained.

This battle was the first to demonstrate Hannibal’s unrivaled tactical brilliance. Though not the climax of his tactical adeptness, Trebia was a masterpiece nevertheless. The virtue of organisation and foresight into the future are key parts of the overall result. If it were not for some parts of the plan, it would have failed as a whole. Ultimately, Trebia demonstrated Hannibal’s ability to pick a battle well, and showed his liking to fighting on his own terms, plus the ability to do so with ease. Furthermore, Hannibal’s ability to use inferior and outnumbered forces is one of his great attributes, and was further expressed at his future battles.
Sempronius returned to Rome defeated, due to his impatience and impetuousness. New consuls were elected in the form of Geminus and Flaminius, and Rome increased the war effort ten fold.

Though not dominant over at this stage, Hannibal had gained many defective allies from Gaul and Latinum. This boosted his forces, and he decided to head south. With extra troops, a revitalised army and added resources, Hannibal was back on the move. Hannibal was on Italian soil, and he was hostile. Now begins the road to Trasimene…




Goldsworthy, A. (2001). “The Punic Wars” - Published by Weidenfeld Military, London.

Polybius. “The Rise of the Roman Empire – The character of Hannibal” (Book IX, chapters 22-26)

Grant, R.G. (2005). “Battle – A visual journey through 5,000 years of combat” Published by Dorling Kindersley Limited, London.

Cornelius Nepos. “De Viribus Illustris – Hannibal”. trans. J. Thomas, 1995


Silverman, D.L. (1996). “Carthage and Rome - The Punic Wars” <> Retrieved 20/3/2007 and 21/3/2007.

References and Notes:
  1. ^ Polybius. “The Rise of the Roman Empire – The character of Hannibal” (Book IX, chapters 22-26)
  2. ^ Goldsworthy, A. (2001). “The Punic Wars” - Published by Weidenfeld Military