Why Don't We Learn from History? - The Battle of Cannae (216 BC).
During his campaign in southern Italy in 216 BC, Hannibal depended for supplies on living off the country or on capturing important food depots. It was this factor that rendered him most vulnerable to defeat. In this spring of 216 BC he had marched south, crossing the River Aufidus, and occupying the town of Cannae, which was an important grain depot for the Romans. Cannae was situated on a hill overlooking a very broad plain across which the sluggish River Aufidus flowed to the sea. Hannibal knew that by seizing Cannae he was not only securing food for his troops, but threatening Rome's supplies to her own army.
At this stage the Roman army was still commanded by the previous year's consuls, Servilius and Atilius. They were not eager to seek battle with Hannibal so near to the end of their consulship. They preferred to wait for the new consuls, Paulus and Varro, and leave the decision of whether to fight or not to them. Nevertheless, the Roman Senate was looking for an opportunity to fight a decisive bettle against the Carthaginians to avenge the defeats of previous years. According to the historian Polybius the Romans fielded eight legions in 216 BC, numbering some 40,000 men, supplemented by an equal number of auxiliaries. If this is true, it makes it the largest Roman army ever raised up to that time. In fact, it was far too large to be commanded by generals of that era; the confusion that ensued in the battle was a result of overloading the simple command structure then in existence. Hannibal, on the other hand, had an experienced staff system and very able subordinate commanders.
He knew he could trust men like his brother Mago, and officers like Hasdrubal, Hanno and Maharbal to control his 40,000 foot and 10,000 cavalry. It gave him an inordinate advantage when the time for action came. In spite of the enormous Roman advantage in infantry far more than could be brought to bear at any one point Hannibal's cavalry was more numerous and more powerful than that of the Romans. In another area that of experience Hannibal had an even greater advantage. His men were generally veteran soldiers who had been with him on numerous campaigns. The Romans, on the other hand, now under the rotating command of Paulus and Varro, were mainly new levies without battle experience.
As Hannibal's strength rested with his cavalry, he was anxious that any battle should take place on the wide plain, on the west bank of the Aufidus.
The Romans, naturally, would have preferred to fight under the hill of Cannae on the east bank. The day the Roman army reached Cannae was one on which Paulus was in command and he suggested to Varro the advantage of crossing the river and assembling on the east bank, which would give Hannibal less chance to use his powerful cavalry. Varro disagreed, and the following day recrossed the river to face Hannibal on the west bank. He knew what was expected of him and the army an immediate and decisive victory and was not the sort of cautious and thoughtful commander who might have manoeuvred to gain an advantage. Instead he relied on weight of numbers alone. So stubborn was Varro that every time Paulus suggested fighting on the hilly ground to the east it only made him more determined to do the opposite. After further crossings and recrossings of the river the Roman army drew up in formation on the west bank, some two miles away from Hannibal's army.
In the June sunshine the new legions unaccustomed to the burning heat of southern Italy, and weighed down by the weight of their armour and their weapons were suffering far more than hannibal's Spaniards and Africans.
When the command reverted to Varro, the latter, abandoning his previous preference for the west bank, ordered his troops to leave camp just after dawn and cross over to the east bank of the river in order to threaten Hannibal's food supplies from Vannae. If Varro had hopped to take Hannibal by surprise he was disappointed. The Carthaginian leader had been waiting for just this moment: the chance to destroy the Romans once and for all. He swiftly crossed the river and drew up his highly disciplined troops in an unusual formation one that was eventually to become the most famous in all military history. On his right flank were the Numidian horsemen whom he knew he could rely upon to scatter the Roman cavalry. On his left alongside the river, he placed the heavy cavalry of the Spaniards and Gauls. But it was in the middle, where he himself took command, that the battle was to be won.
Most of his Spanish and Gaulish infantry was massed in the centre, facing the Roman legionaries whose lines stretched back for hundreds of yards. Through skilful manoeuvring Hannibal had secured the advantage of both sun and wind; the Romans suffering the unpleasant effect of both the burning sunlight and the sand whipped into their faces by the scirocco.
As the Carthaginians began to advance it was apparent that their infantry centre was drawn up in a convex shape. But the early exchanges were between the rival horsemen. The Spanish heavy cavalry routed their Roman opponents and quickly drove them off the plain. On the other wing the Numidians had already routed the Roman auxiliary cavalry. With the latter fled Varro, the consul who had foolishly sought the battle.
In the centre Hannibal's infantry was gradually giving way, as the Romans began to flatten the Carthaginian line. Almost imperceptibly the convex shape had become concave or U-shaped. Sensing a breakthrough, the Roman commanders urged on the massive wedge of legionaries. But as the Spaniards and Gauls give way in the centre, the two wings of African troops began to curl round the Roman flanks. It now became apparent that the massed legionaries in the centre were being enveloped by the Africans. At the same time the Carthaginian cavalry, returning from their victory over the Roman horse, now struck the Roman legionaries form the rear.
Hannibal could see that the moment had arrived to spring the trap, and he ordered a trumpeter to make the signal. At once the Africans completed their double envelopment, by which the huge mass of Roman legionaries was completely surrounded by the Carthaginian army. It was a tactical masterpiece, and one that has inspired generals right through the ages. The battle now turned into one of the most terrible massacres in history. The killing at Cannae that day exceeded even that of 1 July 1916, when the British were slaughtered on the Somme. Never before had the Romans raised so many men for battle, but now they were trapped so tightly that only those at the extreme edges could even lift their weapons or reach their opponents.
Hour after hour passed and the killing went on. So vast was the death tool that ancient writers could hardly contain their disbelief. The lowest figure too low in view of the impossibility of escape for the Roman footsoldiers was a mere 20,000 killed, while Appian and Plutarch speak of 50,000 dead, Quintilian 60,000 and Polybius 70,000. Modern historians have learned to doubt the fantastic figures for armies and casualties given by medieval chroniclers, but it is implausible that casualty figures for this battle could be much lower than 40,000 killed, and they were probably far higher.
Of Hannibal's genius there can be no doubt, but one is forced to the conclusion that the split command of Paulus and Varro contributed significantly to the Roman defeat in view of their obvious incompatibility as commanders. Facing such a skilled opponent, Paulus felt inclined to adopt a more cautious approach, while Varro, presumably underestimating Hannibal or having too much confidence in mere weight of infantry numbers, wanted to press for immediate action. Hannibal might well have defeated Paulus as totally as he had defeated Varro, yet one suspects that few Roman generals would have fallen so completely for his tactics. Varro was a headstrong fool. Leading with his chin he was always vulnerable to a counterpunch. The bunching together of the legionaries was poor generalship once the first two or three ranks were engaged there was absolutely nothing for the rear ranks to do other than wait until the men in front of them were killed.
Piling more and more men into the centre was a dangerous tactic once the Raman cavalry had been defeated. But for all Varro's blunders nothing should detract from Hannibal and his strategic masterpiece on the plains of Cannae.
The Guinness Book of More Military Blunders by Geoffrey Regan