Tiberius Sempronius Longus (consul 218 BC) in the context of "Capture of Malta (218 BC)"

The Battle of the Trebia (or Trebbia) was the first major battle of the Second Punic War, fought between the Carthaginian forces of Hannibal and a Roman army under Sempronius Longus on 22 or 23 December 218 BC. Each army had a strength of about 40,000 men; the Carthaginians were stronger in cavalry, the Romans in infantry. The battle took place on the flood plain of the west bank of the lower Trebia River, not far from the settlement of Placentia (modern Piacenza), and resulted in a heavy defeat for the Romans.

War broke out between Carthage and Rome in 218 BC. The leading Carthaginian general, Hannibal, responded by leading a large army out of Iberia (modern Spain and Portugal), through Gaul, across the Alps and into Cisalpine Gaul (in northern Italy). The Romans went on the attack against the reduced force which had survived the rigours of the march, and Publius Scipio personally led the cavalry and light infantry of the army he commanded against the Carthaginian cavalry at the Battle of Ticinus. The Romans were soundly beaten and Scipio was wounded. The Romans retreated to near Placentia, fortified their camp and awaited reinforcement. The Roman army in Sicily under Sempronius was redeployed to the north and joined with Scipio's force. After a day of heavy skirmishing in which the Romans gained the upper hand, Sempronius was eager for a battle.

Publius Cornelius Scipio (died 211 BC) was a general and statesman of the Roman Republic and the father of Scipio Africanus.

A member of the Cornelia gens, Scipio served as consul in 218 BC, the first year of the Second Punic War. At the outbreak of the war, he was ordered to conduct the war effort in the Iberian Peninsula and confront Hannibal himself, while his fellow consul Tiberius Sempronius Longus was allocated Sicily and Africa. Scipio was given permission to recruit two Roman legions, 14,000 allied infantry, 1,600 allied cavalry and given 60 quinqueremes. He sailed with his army from Pisa with the intention of confronting Hannibal in Hispania. Stopping at Massalia (today Marseille) to replenish his supplies, he was shocked to discover that Hannibal's army had moved from Hispania and was crossing the Rhône. Scipio disembarked his army and marched to confront Hannibal, who, by now, had moved on. Returning to the fleet, he entrusted the command of his army to his brother Gnaeus Cornelius Scipio Calvus and sent him off to Hispania to carry on with the originally intended mission. Scipio returned to Italy to take command of the troops fighting in Cisalpine Gaul.