The Disaster at Cannae

Just as our own Second World War overshadows the First, the Second Punic War made the First look like a ping-pong match. Hannibal Barca, the fearsome Carthaginian leader, had marched through the Alps, allied with several Gallic tribes, and made it his mission in life to humiliate every Roman army that tried to stop him. Thus, Quintus Fabius Maximus was given the title of prodictator, which means acting dictator, and given but one task: stop Hannibal. In hindsight, Fabius appears to be one of the wisest military men in Rome because after closely studying the Roman defeats at Trebia and Trasimene, he knew better than to allow Hannibal to decide the conditions of battle.

Instead of assaulting this army of 56,000 with his much larger force, he shadowed Hannibal during his march through southern Italy, staying up on high defensible ridges and mountains rather than meeting them openly. With enough patience, his strategy probably would have succeeded in either forcing Hannibal to fight on Roman terms, or flee home before his forces dwindled or mutinied. Hannibal tried everything to force a Roman confrontation, pillaging and raiding the countryside and devastating the landscape the Romans had fought so hard in securing a few generations before. However, Fabius was not like the previous hot-blooded Romans that Hannibal had so easily goaded into a fight they couldn't win. His patience meant that the Carthaginian forces had to spend the winter in southern Italy, cut off from their supply and forced to forage in the snow.

The rest of Rome was not sold on Fabius' pragmatism, however, and as soon as his term as prodictator was up, he was denied reelection and two Consuls served in the executive, both of whom favored an aggressive strategy against Hannibal. They were authorized to raise eight instead of the traditional four legions, which comes to 40,000 heavy infantry. In addition, their subservient Latin allies were levied for an additional 40,000 foot soldiers, along with 6,000 Roman and Allied cavalry, so that they outnumbered the Carthaginian troops almost 2 to 1.

Hannibal seized a valuable supply depot in Cannae and the huge Roman army came to face him in open battle. There was some contention among the two Consuls who led the army, with Varro favoring a pitched battle anywhere, anytime, and Paullus favoring a more prudent course of waiting for a better opportunity. On his day of command, Varro ordered his troops into action, changing their formation somewhat to accommodate his sense of tactics. Since they were fighting on an open plain, he had the maniples, who were normally spread out to allow for greater movement and flexibility, pushed together and had the Principes come up close behind the Hastati in an almost-phalanx way.

Hannibal advanced his line to meet the enemy, forming his troops into a “v” formation, pointing their axis toward the Roman line. Varro, believing that this would allow his troops to punch through the line and surround the enemy, advanced his own troops hurriedly, hoping to catch Hannibal off guard. However, as the bold Romans charged, the Carthaginian troops at the very front fell back to the solid line behind them, causing the Romans to charge faster and lose their cohesion, thinking that the enemy was already running away. This gave an opportunity for Hannibal's cavalry to do its work. They charged the opposing Roman cavalry, who were fewer in number and not near as well-equipped, and caused them to rout without much difficulty. Here's a handy diagram to illustrate:

Then they turned their attention to the battle-frenzied infantry line, flanking the Triarii in the rear as they charged forward. Before the Romans had time to react, they were surrounded on all sides, in the center of a deadly crush of arms from both footmen and cavalry. The army was utterly destroyed, according to Polybius around 70,000 died and 10,000 captured with only a few thousand escaping, while Hannibal's forces only suffered around 8-9,000 casualties.

The Senate felt the need to deal with Hannibal quickly because they feared that the other Latin cities would join with Hannibal if he were allowed to roam unchecked for too long. Ironically, it was his victory at Cannae that motivated many former allies of Rome to switch sides and declare for Carthage, including Macedonia, Syracuse, and several Latin cities. After this decisive victory, the Romans saw the need for prudence and pursued a Fabian policy of containment, which was Hannibal's ultimate undoing as he continually tried to replenish his forces for a siege that would never succeed. In the end, it was only by using Hannibal's own tactics against him that the Romans would ever see victory in the Second Punic War.

Pax vobiscum