The Battle of Cannae: Fact file

War: Second Punic War

Dates: 2nd August 216 BC

Place: Cannae, Italy

Belligerents: The Army of Carthage and the Roman Republic

Described variously as ‘one of the most pivotal battles in Western history’, ‘Ancient Rome’s darkest day’ and ‘one of the most spectacular military victories of all time’, the Battle of Cannae fought between the forces of Carthaginian general Hannibal Barca and the army of the Roman Republic under consuls Lucius Aemilius Paullus and Gaius Terentius Varro came to define military tactics for the next two thousand years.

In the second century BC, Carthage and Rome were two of the ancient world’s great Mediterranean powerhouses but Roman military tactics were still being developed and refined. Roman victories in the First Punic War (264 BC – 241 BC) relied essentially on numerical superiority to overwhelm the enemy, with light infantry on the front line hiding heavy infantry behind them and a mix of light and heavy on the flanks.

The tactic of throwing as many men as possible at each battle worked for a while until they ran into Hannibal, a strategic genius the likes of which the might of Rome had neither encountered before, nor was prepared for. The Romans were about to get schooled in military tactics from a supreme warrior who fought like no other before him.

After Carthage’s defeat in the First Punic War, a territorial dispute that had devolved into an existential duel with both sides vying for supremacy, the Romans became the de facto dominant power in the region.

Hannibal’s father Hamilcar Barca was convinced that the key to strength, both economic and military, lay in the control of the mineral-rich region of Iberia. After Barca the Elder’s death in 221 BC, Hannibal, by then the commander of the Carthaginian forces, led a mercenary army of Libyans, Spaniards, Numidians and Celts across the Alps into Italy in 218 BC.

Few tales of ancient warfare can compare to the epic grandeur of Hannibal’s march. He was youthful and energetic and commanded the utmost respect from his multi-national army. After taking the city of Saguntum, a Roman ally in southern Spain, he set off with 40,000 infantrymen, 8,000 cavalry and 38 war elephants. He traversed the mountains itching for a fight.

Advancing through Italy, Hannibal’s men took villages along the route and were victorious in two notable battles against the Romans, in Trebia at the Ticino River and at Lake Trasimene (often described as the largest ambush in history). By 217 BC, Carthage held all of northern Italy and the Roman senate started to look over their shoulders, fearing an assault on Rome itself.

In what became a grave strategic error that had the potential to threaten the entire Republic, the commander of the Roman army, Quintus Fabius Maximus’s non-confrontational policy of attrition, essentially annoying Hannibal and attempting to thwart him through the use of strategic movement rather than full engagement, wasn’t working. The senate wanted – needed – more.

Following the losses at Trebia and Trasimene (where Hannibal’s men killed as many as 50,000 Romans), the Romans elected Lucius Aemilius Paullus and Gaius Terentius Varro and to meet the demands of the Senate and people, equipped them with the largest army the Republic had ever assembled. Some say numbers totalled upwards of 90,000 although 50-70,000 is now widely considered to be more accurate.

They had one mission – confront Hannibal’s army head-on and crush them.

Rarely did ancient historians offer exact dates for the events they described but Roman provincial Macrobius Ambrosius Theodosius, citing the largely unknown Roman historian Quintus Claudius Quadrigarius put the date of the battle at ante diem iiii nones Sextilis, or August 2nd.

It was showtime. Hannibal wanted victory; the Romans needed victory.

The Carthaginians (numbering around 40,000) stormed into southern Italy, camped at Cannae and waited. Not by chance. Nothing Hannibal did was by chance. Cannae was a strategically important grain supply post and on the Aufidus river (now known as the Ofanto) and in southern Italy in August, then as it is now, drinking water was as important as weapons.

On the morning of ante diem iiii nones Sextilis, the two armies – something like 100,000 men – faced off on a boiling hot, dust-blown plain and prepared for battle.

Despite a series of defeats, Varro and Paullus had every reason to be confident of victory at Cannae, and in fact sources at the time described Varro (who would later be scapegoated for his role at Cannae) as overconfident, even rash. By contrast, Paullus was from an established military family and justifiably cautious about what he was about to walk into. Their army was fighting for the honour of Rome while Hannibal’s ragtag bunch of Africans, Gauls, Gallic Celts, Spaniards, Libyans and myriad mercenaries were a very long way from home.

The Roman army set up in a traditional block formation with infantry protected by cavalry on both flanks and Varro had hoped to use his superior numbers like a battering ram to push through the middle of the Carthaginian lines - but of course Hannibal was waiting for this exact movement.

Relying on the elasticity of his formation, Hannibal placed his Gallic and Spanish infantry (deemed to be the weakest of his men) in the centre, two groups of Africans on their flanks and the cavalry on the wings. However, before engaging, his line created a crescent-shaped formation with the centre advancing forward and the flanks en échelon, that is positioned diagonally behind each other.

As the Roman infantry continued to sweep forwards (and giving them the impression that forward movement equalled winning), they became too closely packed and all but abandoned their rigid lines.

It was then that Hannibal gave the order that spelled the end for the Roman army.

On his signal, the Libyans on the flanks pivoted inwards and attacked the Roman infantry who were advancing up both sides, closing in on them like a vice. While this was occurring, the Carthaginian cavalry defeated the Roman cavalry on each side of the battle lines and then swept forward on both flanks to encircle the Roman army and close the trap. Once the Romans were shorn of their cavalry protection, the Carthaginians wheeled around to attack as many as 70,000 legionnaires from the rear, unprotected and completely surrounded.

While Hannibal could smell victory (literally and metaphorically), the battle wasn’t yet over. The surrounded Romans refused to hoist the white flag so the Carthaginians began the gruesome task of slaughtering them, one man at a time.

For hours after the main fight ended, the battlefield at Cannae was transformed into a blood-soaked killing field. A few thousand managed to break the circle of steel and ran for it but the rest were unceremoniously massacred.

Chronicler Titus Livius, known as Livy, later wrote ‘Some were discovered lying there alive, with thighs and tendons slashed, baring their necks and throats and bidding their conquerors drain the remnant of their blood. Others were found with their heads buried in holes dug in the ground. They had apparently made these pits for themselves and heaping the dirt over their faces to shut off their breath.

By sundown, anywhere between 50,000 and 70,000 Roman bodies littered the battlefield at Cannae, something in the order of 20 percent of all Roman fighting men between the ages of 18 and 50. This number included veteran patricians such as Gnaeus Servilius Geminus and Marcus Minucius Rufus, 28 of 40 tribunes, around 80 of senatorial or high magistrate rank, and at least 200 knights. Paullus was killed, Varro fled the battlefield with the last of the Roman and allied cavalry. By contrast, Hannibal lost 6,000 men.

More soldiers died at Cannae than on the first day of the Battle of the Somme on the Western Front on 1st July 1916, by far and away the deadliest day in the history of British warfare. The Romans lost seven times as many men as were killed at the Battle of Gettysburg.

It was a day of utter and unimaginable brutality the likes of which has never been seen since.

Pulitzer prize-winning historian Will Durant said that ‘The Romans could not readily forgive Hannibal for winning battles with his brains rather than with the lives of his men. The tricks he played upon them, the skill of his espionage, the subtlety of his strategy, the surprises of his tactics were beyond their appreciation. It was a supreme example of generalship, never bettered in history.’

There was chaos when word of the crushing defeat reached Rome. Numb panic gripped the city, women rushed to the temples to grieve for their fallen sons, brothers, husbands and fathers. Appian wrote that ‘Multitudes thronged the streets uttering lamentations for their relatives, calling on them by name, and bewailing their own fate as soon to fall into the enemy’s hands.’

Hannibal was urged by Maharbal, one of his most trusted lieutenants, to march on Rome but he chose not to, believing his army was too weak. Livy reported later that Maharbal told Hannibal that he knew how to win battles but he didn’t know how to take advantage of such victories.

After a brief period of mourning, Rome refused to yield, they rejected Hannibal’s offer of peace and even refused to ransom his men taken at Cannae. The citizens of Rome were tasked with rebuilding the army’s defences and the army itself grew, phoenix-like from the flames with amongst other tactics a lowering of the age of recruitment and the enlistment of convicts and slaves in return for their freedom.

Maharbal was right. The legendary commander didn’t know how to take advantage of what became known as one of history’s greatest military victories. He continued through Italy for a few more years looking for another Cannae but his isolated, war-weary army – such as it was by then – slowly withered away and many returned from whence they came.

Perhaps the greatest Roman legacy and arguably the clearest demonstration why they became one of the world’s great empires was their survival.

‘No other nation surely would not have been overwhelmed by such an accumulation of misfortune’ – Livy.

The Second Punic War continued for another 15 years. In 202 BC, one of the few survivors of Cannae, Publius Cornelius Scipio Africanus, known variously as Scipio Africanus Major, Scipio Africanus the Elder and Scipio the Great who was embarrassingly exiled to Sicily after the shame in 216 BC, took on Hannibal’s army at the Battle of Zama using tricks and tactics learned at Cannae and won his redemption in spectacular style. Hannibal was defeated by the very strategies that made his name.

The reign of Carthage as a serious military power was effectively over and the Romans came to rule the known world for the next 600 years.

Hannibal’s status in the pantheon of history’s greatest military commanders is cemented – so much so that there are statues of him in Rome as testament to a most worthy adversary – and his military genius is still taught in military academies the world over as the perfect way to destroy a numerically superior force using encirclement. He has been the subject of fascination for military commanders ever since, including Frederick the Great and Napoleon.

‘Every ground commander seeks the battle of annihilation; so far as conditions permit, he tries to duplicate in modern war the classic example of Cannae.’ General Dwight D Eisenhower.