The Carthaginian victory over Rome at the Trebia River in 218 BC opened Hannibal's Italian campaign and demonstrated Roman vulnerability in pitched battle.
Key Facts
- Date
- 22 or 23 December 218 BC
- Each army strength
- ~40,000 men
- Romans who escaped
- 10,000 under Sempronius
- Hannibal's army after battle
- grew to 60,000 with Gallic recruits
- Location
- West bank of lower Trebia River, near Placentia
By the Numbers
Location
Cause → Event → Consequence
War between Carthage and Rome broke out in 218 BC. Hannibal led a large army from Iberia through Gaul and across the Alps into Cisalpine Gaul. After defeating Roman cavalry at the Battle of Ticinus and wounding the Roman commander Scipio, the Romans consolidated near Placentia and awaited Sempronius's reinforcing army from Sicily. Hannibal then used a skirmish to inflame Sempronius's eagerness for a decisive engagement.
Hannibal used Numidian cavalry to lure the Romans out of their camp onto ground of his choosing. Fresh Carthaginian cavalry routed the outnumbered Roman cavalry, while Carthaginian light infantry outflanked the Roman infantry and a hidden force attacked the Roman rear. Most Roman units collapsed, with the majority killed or captured. Only 10,000 men under Sempronius maintained formation and fought their way to Placentia.
The defeat established Carthaginian dominance in Cisalpine Gaul, prompting Gallic recruits to join Hannibal and swelling his army to 60,000. The following spring he advanced into Roman Italy and won at Lake Trasimene, then in 216 BC inflicted the catastrophic defeat at Cannae—the third of three major Roman military disasters in the war's first three years.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Hannibal.
Side B
1 belligerent
Sempronius Longus, Publius Scipio.