Battle of Lake Trasimene | History, Casualties & Significance

The Romans were within a day's march when the Carthaginians reached the north shore of Lake Trasimene on June 20, and Hannibal decided to stand and fight. After making camp on the lake shore, Hannibal ordered his cavalry and light infantry on a risky nighttime march into the hills, placing them in position to ambush the oncoming enemy. Early the following morning, the Romans began advancing upon the Carthaginian encampment to their east. The Romans were expecting a battle, but Flaminius did not reconnoiter the hills on his left flank to the north of the lake.

The Romans first encountered the Carthaginian forces arrayed to defend their camp on the lake shore, probably consisting of Hannibal's African and Iberian heavy infantry. Once the battle was joined, Hannibal signaled to his forces in the hills, including the allied Gauls, to descend and encircle the Romans. The Carthaginian cavalry had been assigned the westernmost position, ideally placed to attack the Romans from the rear. According to Polybius, Flaminius was caught off-guard. The bulk of the surrounded Roman army fell into disarray and was destroyed, with some fleeing into the water, where they drowned or became easy prey to Carthaginian cavalrymen. The leading Roman contingent, numbering some 6,000 men, managed to break through the encirclement and continued to march east. Before the day was out, they were caught and surrounded by pursuing Carthaginians, and the Romans were forced to surrender.

After the battle, the Carthaginians continued their march into Roman territory, reaching as far as the southern region of Apulia. With their military power considerably reduced, the Romans feared confronting Hannibal in the field. They turned to more defensive tactics, seeking to wear down the invaders until their armies were replenished. This lull in the Second Punic War lasted for another year, until 216 BC. The return of the Romans to their traditionally aggressive mode of war-making soon led to their greatest military disaster in the Battle of Cannae, where Hannibal and his army surrounded and slaughtered 70,000 Romans.

The Second Punic War dragged on in Italy for another decade, with the Romans returning to a strategy of avoiding confrontation with Hannibal. A Roman counterattack on the Carthaginian heartland in Africa finally led to Hannibal's recall from Italy and his ultimate defeat in the Battle of Zama in 202 BC.

Battle of Lake Trasimene Casualties

The Roman army was destroyed in the Battle of Trasimene, but ancient sources differ in the proportion of soldiers killed or captured. The contemporary senator Fabius Pictor reported that 15,000 were killed and 10,000 dispersed. The historian Polybius agrees with the number of deaths but states that the bulk of the remainder were captured. Roman prisoners were sold into slavery, but captives from other Roman-allied cities were treated more kindly. This was a deliberate tactic on Hannibal's part to entice Italian cities to defect to his side.

The Carthaginians, by contrast, suffered only minimal casualties. Polybius puts the number at 1,500 dead, with the greatest number from among the Gauls allied with Hannibal. On the other hand, the historian Livy claims that 2,500 died in the battle, and many more died later of their wounds.

Hannibal won an early victory over the Romans in the Battle of the Trebia in Northern Italy, then marched south into Italy with an army of 50,000 men. On June 21 of 217 BC, Hannibal succeeded in ambushing another Roman army led by a consul named Gaius Flaminius on the shores of Lake Trasimene, near the border of modern Tuscany. Carthaginian forces hidden in the hills above the lake surrounded 25,000 advancing Romans, most of whom were killed or captured. Flaminius was caught completely by surprise and died at the hands of a Gaul named Ducarius. With his victory at Lake Trasimene, Hannibal was free to advance deeper into Italy. The Romans were left in desperate straits, and Fabius Cunctator was appointed as Dictator in response. His Fabian strategy of avoiding direct combat ultimately saved Rome from Hannibal's invasion, though the Romans were dealt a crushing defeat in 216 BC at the Battle of Cannae.