4. Hannibal Surprises the Romans at Lake Trasimene
In 218 BC, Carthaginian general Hannibal Barca defeated two Roman armies in northern Italy. The following year, Rome sent both of her consuls for 217 BC to deal with him. One of the consuls, Gaius Flaminius, gathered the survivors of the earlier defeats, and reinforced by new recruits, assembled an army of about 30,000 men and marched south to defend Rome. Hannibal overtook and passed Flaminius, and got his own army between the Romans and their home city.
Hannibal thus pulled off one of history’s earliest strategic turning movements, to get between a defender and his base. To draw out Flaminius and goad him into giving battle, Hannibal began devastating and burning the countryside as he marched south. That forced Flaminius to hurry his army to catch up with Hannibal before the Carthaginian reached Rome.
Hannibal continued his march southward, with Flaminius in hot pursuit, until the Carthaginian came upon a suitable spot for an ambush at Lake Trasimene, about 80 miles north of Rome. There, a stretch of the road passed through a defile, between the lake’s northern shore and forested hills. Hannibal camped on the eastern end of the defile, within clear of sight of Flaminius when he got there.
The Carthaginian formed his heavy infantry in front of the camp, blocking the road down which the Romans would arrive, to challenge them into battle. He concealed his cavalry, light infantry, and Gaulish allies, on the forested hills north of the road, and waited. When Flaminius arrived at the defile’s western entrance on the morning of June 24th, 217 BC, and saw the Carthaginians arrayed in front of their camp to offer battle, he was relieved to have finally caught up with his quarry. Unwilling to risk Hannibal’s slipping away again, he immediately advanced upon the Carthaginian.
Flaminius in his eagerness failed to scout the hills north of the road before marching into the defile. The Carthaginian’s concealment was further helped by a fortuitous fog that morning, which reduced visibility. Once the last Roman entered the defile, trumpets were blown and the trap was sprung. The concealed forces rushed down from the hills to fall on the flank and rear of the Romans, who suddenly found themselves surrounded by the enemy on east, north, and west, while the lake blocked them to the south. Flaminius’ army was wiped out. Out of 30,000 Romans, about half were killed or drowned, and the rest were taken prisoner. In terms of the number of combatants involved, it was history’s biggest tactical military ambush.