Why is the Battle of Cannae so famous?
“Never, except when Rome itself had once been captured, was there so much terror and confusion within the walls. I shall confess that I am unequal to the task of narration, and will not attempt to provide a full description, which would only fall short of the truth.” -(Livy)
With a huge force of 80,000 legionaries – double the size of the Carthaginian infantry – it is difficult to envisage how they could have lost. Despite its size, the Consul Varro had chosen to have a deep line, rather than a long one.
Thus instead of outflanking the Carthaginian army, his line either matched, or was slightly shorter, than theirs. Hannibal’s false retreat of the centre had caused the Roman line to pile into the centre, allowing his smaller force to surround the much larger Roman army.
The Romans never had more than 2,000 men facing the Carthaginian line at any one time. And although the formation was 35 – 50 ranks deep, this counted for nought. Once the forward momentum war became arrested. Now the numbers worked against the legions, with them pressed together into a crush and unable to draw their swords.
Despite encircling the Roman force, there could be no quick massacre. This was an age without gas, guns and bombs. As a result, all of the killing of this huge host would have to be done by hand. Furthermore, at great risk to the Carthaginians.
Some 6,000 Carthaginians would die in achieving the victory. A huge cost to Hannibal’s army that historians often overlook in the context of this comprehensive victory. This was not the classic case of breaking an enemy and then cutting them down as they ran – this was encircling and then massacring them.
Once the encirclement was complete, up to 600 Romans would die every minute.
This would be the highest kill-per-minute ratio of any battle until the Battle of the Somme some 2,133 years later.
There would be 30,000 gallons of blood spilt. Polybius gave the Roman dead at 70,000, with 10,000 captured and 3,000 survivors, with only 370 survivors from the Roman cavalry. Livy gives 45,500 dead infantry and 2,700 dead cavalry, with 3,000 infantry and 1,500 cavalry captured, plus 2,000 fugitives at the village of Cannae, 7,000 captured at the smaller legionary camp and 5,800 at the larger.
The Consul Paullus – who had wanted to withhold battle – was among the dead, although he co-Consul Varro escaped. Also among the senior soldiers to perish were two quaestors, 29 of the 48 military tribunes, including the previous year’s Consul Geminus, and 80 Senators.
For many of those trapped in the centre of the giant crush, there was little they could do besides wait to die. With their arms pinned to their sides, their heads made easy targets for Punic javelins. Many fell on their swords, knowing death was their only escape. Many dug holes and buried their heads in the ground.
When the Carthaginian soldiers waded through the battlefield, exhausted survivors and the wounded merely presented their necks to them.
Darkness would be their only escape.
Only 14,000 Romans would escape from the field, including Scipio the Younger who broke out of the encirclement with 500 men and made it to the town of Canusium.
This was a catastrophic loss for Rome – the death of a generation. In addition, crippling for the government, with so many from the ruling positions killed on the field. It is impossible to imagine what this would have looked like. Much less how an ancient society – when populations are far smaller than modern times – could cope with such a loss. This was a plain with the equivalent of a large sports stadium of corpses, the sky dark with crows, the air filled with the buzzing of flies, the air having the metallic taste of blood.
This was more dead in one day than the US lost in the entire Vietnam War.
Cannae would become one of the greatest defeats in Rome’s history, and a brilliant piece of military strategy that generals to this day attempt to emulate in surrounding and annihilating an enemy army – including in the Gulf War. Napoleon was critical of Hannibal for employing such a risky tactic, stating that a smaller army should never seek to encircle a larger one as he became an advocate of overwhelming opponents, stating:
“Quantity has a quality all of its own.”
Despite this, Cannae would be the zenith of Hannibal’s campaign – the rest of the Second Punic War would never see his army reaching such dizzying successes.
It is difficult to understand how the Roman Republic could not have merely folded after Cannae. Most civilisations could take one heavy hit, and then would have to sue for peace. Rome had now taken three, and yet still refused to surrender. Alexander had defeated the Achaemenid Empire three times before it fell. And now the Roman Republic, which controlled far less territory, was persevering after similar setbacks. It displayed its trademark belligerence, digging in to prolong the war. Just as the allies sought to avoid fighting Napoleon directly, so too would the Romans now avoid Hannibal.
Hannibal was perhaps somewhat naïve in thinking Rome could be utterly defeated on the battlefield. For Italy still had huge resources of manpower.
There were 325,000 men in Italy when Hannibal invaded, with 250,000 of those of fighting age. That number would continue to swell, and the 17 years of fighting after Caesar crossed the Rubicon saw 420,000 Italians fighting.
Rome would raise an average of two legions per year after Cannae, though Hannibal’s plan of getting the Italian allies also started to bear fruit.
News of the devastating defeat shocked Italy, and many began to question whether it would be Carthage. Rather than Rome, which would be the dominant power on the peninsula. Despite all this, the option of “joining” Carthage was never particularly enticing. Rome still has restrictive citizenship, but franchised far more people than Carthage did. Rome had taken the Greek concept of “polis” and advanced it to “natio”. And its allies could see how they could climb the ladder to become more involved with the republic. And ultimately become Roman themselves.
In the short term, Rome was in complete disarray.
The best legions of Italy were destroyed, and the remnants utterly demoralised. Rome declared a national day of mourning, and there was not a single person in the city without a relative among the dead. Twice the Romans resorted to the abhorrent practice of human sacrifice, burying people alive in the Forum and abandoning an oversized baby in the Adriatic – the last instance of human sacrifice in Rome.
In three campaigning seasons, Rome lost a fifth of the entire male population of over 17s. Moreover, with 150,000 of them dead. Most of southern Italy now defected to Carthage, with Capua and Tarentum among two of the largest cities to renounce their allegiance to Rome.
“How much more serious was the defeat of Cannae than those which preceded it, can be seen by the behaviour of Rome’s allies; before that fateful day, their loyalty remained unshaken, now it began to waver for the simple reason that they despaired of Roman power.”
Sicily’s Greek cities rose in revolt, while Philip V of Macedon proposed an alliance with Hannibal, to essentially flank Italy.
The new King of Syracuse, Hieronymus – the only independent city on the island – declared for Hannibal. The road to Rome now lay open. It seemed only a matter of when, not if, Hannibal would besiege the defenceless city. And finally crush the Roman Republic to avenge Carthage’s loss in the First Punic War.