How Failure at the Battle of Cannae Nearly Destroyed the Roman Republic

By John Trumbull (1756-1843) - Yale University Art Gallery - The Death of Paulus Aemilius at the Battle of Cannae, Public Domain,
March 2, 2020 Topic: History Region: Europe Blog Brand: The Buzz Tags: Battle Of CannaeRomeCarthageHannibalSecond Punic War

How Failure at the Battle of Cannae Nearly Destroyed the Roman Republic

A terrible loss.

The legionaries kept up the pressure as the Carthaginian center began to retreat. The Roman flanks soon drew in toward the center far enough that they were even with the Libyo-Phoenician infantry positioned to either side of the Iberians and Gauls. Now came a crucial point in the battle. The contracted Roman line focused on the center, where at long last success over Hannibal seemed imminent. This left the flanks vulnerable. Hannibal saw this and took advantage of the situation. The Libyo-Phoenician infantry wheeled toward the shortened Roman flanks and charged in at them, fresh troops crashing into the tightly packed legionaries, many of whom were already tiring from pushing against the center. 

Still, the battle was not yet over. The Romans must have kept their discipline, reforming their ranks to deal with the new threat. Such actions would have been hasty and extremely difficult, given the lack of space for the Roman soldiers to maneuver, for as they advanced toward the center they naturally pressed together. Yet the battle was not entirely lost at this point, so the Romans must have succeeded in quickly creating a defensive line in the constricted space. This did leave each individual with less room to use his weapon or position his shield. The Roman line remained coherent but its forward momentum was likely checked, allowing the battered Carthaginian center a brief but crucial reprieve. 

While the Roman infantry realigned to deal with this new and dire situation, the 4,000 Numidian horsemen took advantage of the change in fortune to charge at the Roman allied cavalry on the Roman left wing. Varro remained with these Allied riders as the Numidians bore down on them, but the circumstances were different on this side of the battlefield. The field was open for maneuver, as Paullus feared when he first laid eyes on the terrain days earlier.

The Numidians harried their foes, advancing and turning away, a more traditional cavalry tactic. “From the peculiar nature of their mode of fighting, they neither inflicted nor received much harm, they yet rendered the enemy’s horse useless by keeping them occupied, and charging them first on one side and then on another,” wrote Polybius. The fighting between the two cavalry forces went inconclusively for a time, but the scales soon tipped against the Roman allied horsemen when the Numidians received reinforcements in the form of the Iberian and Gaulish riders led by Hasdrubal. Once finished with the Roman cavalry by the Aufidius River, Hasdrubal reformed his men and rode to the assistance of the Numidians, adding his numbers to theirs. Daunted by the overwhelming numbers, the Roman cavalry fled.

Hasdrubal then made a cunning and sage decision. He directed the Numidians to pursue the fleeing Roman allies. This prevented them from reforming and returning to the battle. Next, he regrouped his own troops and together they rode back to the battle, joining the Libyo-Phoenicians.

At that point, the Roman infantry was in serious trouble. It had been abandoned by its cavalry as Hasdrubal’s force rode into its rear. By this time, the Roman rear ranks were probably turned about to face the new threat since the Libyo-Phoenicians were so deep on their flanks. It is also likely the Roman velites light infantry were present in the Roman rear, since they would normally withdraw through the main lines to the rear after they skirmished. These lightly armed and armored fighters were ill equipped to face enemy cavalry. The Carthaginians launched rolling attacks all along the Roman rear line, encouraging the nearby Libyo-Phoenicians as much as they disordered the Romans.

Despite the cavalry attacks and Carthaginian infantry swarming around them, the Romans still held firm. Many of their leaders set the example, including Paullus. He suffered a wound from a sling stone early in the fighting, according to Roman historian Livy. Despite his injury, Paullus moved along the lines, giving encouragement and exhorting his men to stand firm whenever it seemed they might break. Eventually the consul grew too exhausted to remain on his steed and his retinue dismounted with him. The Carthaginians attacked them, angry that the Romans refused to surrender despite the growing odds against them. Paullus’s men were slowly cut down. A few of them climbed back on their horses and rode away, but Paullus was not among them. He stayed behind and fought on until a band of Carthaginians cut him down.

Servilius was also killed about the same time. The loss of both generals caused the Roman infantry to start breaking. Groups of men within the cauldron began trying to push through the surrounding Carthaginians and make their escape. Even this became ever more challenging as the Carthaginian infantry pushed inward. More and more Romans in the outer ranks were killed or wounded and had to be pulled back. Being behind the front ranks provided no safety, however. Sling stones and javelins from the light infantry rained into the Roman center while the spearman and swordsmen around the shrinking perimeter hacked and thrust into legionaries so tightly packed some could not use their own weapons.

This continued until the Romans lost all cohesion and became merely a panicked mob awaiting death from all around them. The outcome was guaranteed as the last men were cut down either in small groups or individually. The immense battle ended with a mass of dead and dying Romans on the field. A few thousand of their infantry managed to break free and escape. They ran off to nearby towns while 300 of the Roman cavalry also escaped. The victorious Carthaginians quickly moved on the Roman camp, killing 2,000 of the troops left to guard the encampment and taking the remainder prisoner. 

The battle was a complete disaster for Rome. The Romans suffered 55,000 casualties compared to 5,700 Carthaginian casualties. Paullus, 80 senators, and 21 tribunes were among the Roman dead. Many of the lost equites were also men of standing or wealth. Varro fled with the remaining allied cavalrymen and survived. He rode with 70 other survivors to Venusia. Polybius would recall his conduct poorly in his later writing.

The battlefield was a horrifying scene, covered in the dead and dying. “So many thousands of Romans were lying, foot and horse promiscuously, according as accident had brought them together, either in the battle or in the flight,” wrote Livy. “Some, whom their wounds, pinched by the morning cold, had roused, as they were rising up, covered with blood, from the midst of the heaps of slain, were overpowered by the enemy. Some too they found lying alive with their thighs and hams cut, who, laying bare their necks and throats, bid them drain the blood that remained in them.”

Hannibal achieved a great victory at Cannae. His double envelopment, in which the forces of one army simultaneously attack both flanks of the enemy army in order to encircle it, became a textbook military maneuver emulated by modern commanders. Hannibal destroyed eight Roman legions and their matching allied legions. The defeat came as a terrible blow to Rome and did serious damage to its reputation.

Some of Hannibal’s generals suggested the army rest after achieving such an overwhelming success, but Maharbal disagreed. He suggested the entire Carthaginian army march on Rome immediately and finish the war. Maharbal even volunteered to ride ahead with his cavalry, believing he could get to the city before its citizens knew he was coming. While applauding Maharbal’s motivation and energy, Hannibal chose not to follow up with the immediate attack. “You know how to conquer, Hannibal, but you do not know how to make use of your victory,” responded Maharbal.

There was truth in Maharbal’s words. Hannibal possessed great tactical skill. He set the conditions for the Battle of Cannae and the Romans obliged, allowing Hannibal to dictate the course of the fighting. Over the course of the war Hannibal did this several times, taking advantage of the Romans’ aggressiveness and impatience. Rome’s martial traditions resided in a belief in the offensive, and Hannibal bled them dearly for their inflexibility.

In the wake of Hannibal’s string of victories, the Greek-speaking cities of southern Italy, Sicily, and Macedon renounced their alliance with Rome. But Rome’s other allies remained loyal. Hannibal eventually offered reasonable peace terms, but the Roman Senate rejected them. 

Hannibal underestimated the Roman will to continue the fight. It did not occur to him that the Romans would refuse to yield and would never accept defeat. The stakes were simply too high. What is more, the sting of the routs the Roman army suffered brought calls for vengeance against the Carthaginians.

Over the course of a two-year period beginning in 214 bc, Rome ultimately captured the Greek city of Syracuse in Sicily. The achievement was the work of Marcus Claudius Marcellus who arrived with a fleet and an army. He had equipped some of his warships with siege engines and ladders to assault the strongly held city from the water.

The brilliant inventor Archimedes developed countermeasures that initially thwarted the Romans. One of these consisted of a hook that could reach out over the water and capsize Roman vessels. The Romans repulsed efforts by the Carthaginians to relieve the city. An elite group of Roman soldiers managed to infiltrate the city. The conquest spelled the end of the independence of the Greek cities in southern Italy and Sicily.