The Battle of Cannae

  By Theodore Felix, 29 May 2007; Revised
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In the year 216 B.C., Hannibal attained what Schlieffen described as “a perfect battle of annihilation”(1), the victory at Cannae. The defeat for Rome was staggering: of an army numbering 80,000 men, 50,000 lay dead in the field; with them the consul, Aemilius Paulus, numerous ex-consuls and 1/3 of the senatorial body. For a moment, the fate of Rome came to be questioned. For the republic, and later the empire, it set the bar for all disasters. It was a defeat that was matched only a few times in the numerous centuries of the empire’s existence.

Hannibal's tactical genius makes Cannae one of the greatest battles of history, and one which was reattempted often with varying degrees of success. Subsequently, Rome's disaster, her stern resolve, and eventual triumph makes the Second Punic War one of the most spectacular tales of antiquity.


Two years prior to this fateful event, Hannibal invaded the Italian peninsula with one goal in mind: crush Roman hegemony. His army was an amalgam force of Libyan, Numidian, Iberian, Gallic and, eventually, Greek and Italic soldiers. The nature of this army could hamper both its unity and its organization; while its largely barbaric character made it extremely difficult for him to besiege walled cities. Hannibal, therefore, could only carry out a “limited war”: he had neither the resources nor the capabilities to destroy Rome.

Instead, his plan was based on bringing Rome a series of defeats that would alienate her from her Italian allies. If he managed to break Rome’s hold, or, even better, bring them against Rome, he could then strangle the republic‘s resources, thus forcing it into a surrender. However, this would require a serious show of force on his part as Rome proved to be more than a resilient power during the first Punic War, catching the better of the Carthaginians through sheer exhaustion. If the plan was to succeed, Hannibal would have to achieve something great: a series of decisive, if not, outright catastrophic victories that would cow the Italian republic.

By 216, Hannibal was achieving what he planned, albeit it the results were not quite what he had expected: exempting various Gallic communities, few to none in Italy had turned on their supposed “Roman oppressor”. In 218, he defeated the consular armies of Tiberius Sempronius Longus and Publius Cornelius Scipio at the battle of Trebia. In 217, he crushed the army of Gaius Flaminius in what was possibly the greatest ambush of antiquity. Flaminius lost his life in the ensuing battle, along with 15,000 other Romans. Between 217 and 216, the Romans relied on the cautious strategy of Fabius Maximus, who refused combat with Hannibal throughout the duration of his post as Dictator as a way to drain the Punic’s resources and morale. The “Fabian tactics”, as it was later coined, succeeded only marginally as his adversary was able to keep his army well intact through the plunder of Italy.

By the end of Maximus’ term, the Romans were, once again, thirsting for battle. The fact that Hannibal could move around Italy at will, flaunting his successes at the cost of Roman “dignitas”, was entirely unbearable and unbecoming. The Republic and the People needed to reassert themselves if they were to maintain their hegemony.

A short interregnum(2) followed Fabius' dictatorship. The senators used this time to review their strategy. Livy is our main source over the discussions that follow; unfortunately, his account is confused. In the end, the two consuls chosen were Gaius Terentius Varro and Lucius Aemilius Paullus, as his colleague. Varro, a novus homo(3), is portrayed as a rash demagogue, gaining popularity with the masses through attacks on the patricians and the delaying tactics of Fabius, while Paullus is portrayed as a modest patrician, fearful of Varro’s irrational mind. This image is greatly influenced by the fact that the Aemilii would continue to play a major role in Roman politics over the next century while Varro would fade away after the disaster. It is diluted even more when we consider that one of our main sources, Polybius, was sponsored by the Scipionic circle, which would merge with the Aemilii(4).

216 Campaign

The Romans now clearly envisioned a confrontation with Hannibal and mobilized accordingly; this time, the weight of the legions would clearly be felt. Though the battles of Trebia and Trasemine ended with a defeat, in both cases the power of the legions was enough to break through the Carthaginian line and escape. The fact, then, was obvious: the Roman brute force was enough to crush their enemy. If they could not succeed in any tactical manner, then, surely, they could in simple power.

Both Livy and Polybius, our main sources, seem to agree on the number of men, the former gives the greatest amount of detail:

Some authorities record that both horse and foot in the legions were made stronger by the addition of 1000 infantry and 100 cavalry to each, so that they contained 5000 infantry and 300 cavalry, whilst the allies furnished double the number of cavalry and an equal number of infantry. Thus, according to these writers, there were 87,200 men in the Roman camp when the battle of Cannae was fought. (5)

The several months of skirmishing under Fabius allowed new recruits to be seasoned; these men were most likely transferred to the new army. Nevertheless, the unprecedented size of the army and the rapidity of the campaign meant that the larger part of the army was never properly trained. The force would be incredibly difficult to manage and maintain; while, at the same time, impossible to maneuver. There was little the army could do except march forward. In the cavalry department, the Romans came short and did not make any attempt to try and match their opponent. They caught the worst of nearly every cavalry engagement prior and must have disregarded any possibility of victory against Hannibal’s powerful force. Instead, the Romans were content so long as their cavalry could hold off Hannibal’s while the infantry tore their opponent apart.

While the Romans organized their massive force, Hannibal maneuvered around Apulia (Puglia), shadowed by Servilius Geminus and Atilius Regulus. The two commanders controlled a small force that was instructed not to engage Hannibal, but to wait for the arrival of the consular army. This allowed Hannibal to capture the rich supply depot of Cannae with ease. With this, he was no longer reliant on foraging; furthermore, the town was also a good look-out point. Now all Hannibal had to do was sit and wait for the Romans to come to him.
Once everything was ready, the two generals marched separately until around Gerunium, where they united and moved towards Hannibal. Paullus is said to have held misgivings upon approaching their adversary: the country was far too flat and, thus, advantageous to cavalry, the weakest department of the Roman army; the strongest of Hannibal’s. Varro moved forward upon his day of command. The hostility against Varro here is universal, Polybius states that his decision is due to inexperience while Livy and Appian see him as nothing more then a demagogue. In reality, the consular army at Cannae was far too large for delaying games; moreover, its size made it so clumsy that any maneuvers were both dangerous and next to impossible. During this time, Hannibal sent a skirmishing group to attack their enemy’s marching column, it was thrown off. 

Paullus must have agreed with Varro’s decision at this point since he moved closer to Hannibal on his day of command. He camped 2/3 of the army on the left bank of the Aufidus(6), making the other 1/3 cross and camp on the right. That same day, Hannibal mirrored Paullus: it was a signal that he was ready to engage. The next day, the entire Carthaginian army came out and offered battle to the consul, Paullus declined: a sign that the misgivings are likely historical. Hannibal then sent out Numidians against Roman foragers and the smaller Roman camp: once again the latter did not react. All sources concur on the Roman reaction:

Caius Terentius [Varro] became more than ever inflamed with the desire of fighting, and the soldiers were eager for a battle, and chafed at the delay. For there is nothing more intolerable to mankind than suspense; when a thing is once decided, men can but endure whatever out of their catalogue of evils it is their misfortune to undergo. (6)

Varro took command of the army the next day: he immediately moved out the army for battle.

The Battle

Once the river was crossed, the larger Roman force united with the smaller one and then went into position. The cavalry was stationed in the wings, the left wing being largely composed of allied cavalry; the right wing on a smaller front since it was positioned near the river, a move that hoped to negate the larger size of the Carthaginian cavalry. The infantry was placed in the center with its “depth of each maniple several times greater than its front”, according to Polybius. The legionaries at Cannae were still fresh and so unfit for shallow depth, the deeper line gave more longevity, speed and intimidation. The Romans faced southward, with their back to the Adriatic. The two consuls took each wing, Paullus the right while Varro the left, since it was the flanks that would need the greatest amount of support. The total size of the active army was probably around 55,000 infantry, in three lines, and 6,000 cavalry. The remaining portion remained in the camp for a possible attack on the Carthaginian camp. The Roman tactic was for the cavalry to hold its ground long enough for the infantry to tear through the thin Carthaginian line.

Hannibal’s first order was to move out his skirmishers, the famed Balearic slingers and spearmen, to screen his deployment. The Gallic and Iberian horsemen were positioned on the left wing, facing the Roman right, whilst the Numidians were place on the right wing. The center, led by Hannibal himself, was composed of Spanish and Celtic infantry, while the Libyans were placed on the infantry wings, next to the cavalry. Polybius notes that the Libyans wore Roman armor acquired at Trebia and Tresamine. The Carthaginian right wing cavalry was commanded by Hanno whilst the left by Hasdubral. The total size of the force was around 40,000 infantry, 8,000 of which were probably skirmishers, and 10,000 cavalry(7). Once the entire army was in place Hannibal ordered the Ibero-Celtic center to serge forward so as to create a crescent towards the Romans. He knew that his adversary would focus on crushing the center and that a single straight line would break far too quickly. By having his center make fist contact, he could draw the entire Roman effort there in order to expose their flanks when his center did break.

The battle opened in the typical manner of classical warfare: skirmishing between light infantry. In this case the Romans far outnumbered the Carthaginians, however, the latter were far more experience than the former. Either way, skirmishing was more of a ritual than anything else, the blind fire meant that neither side suffered any serious casualties. After a while, the skirmishers were withdrawn, however, very likely, they continued to give support to the main body.

At the onset of the battle, as the skirmishers clashed, Hasdubral launched a fierce attack against the Roman right wing. The narrow space between the river and infantry meant that none of the usual maneuvering occurred.  Instead, according to Polybius and Livy, it was a “barbaric” affair where many of the Romans dismounted and fought as infantry. The account is somewhat confused and colored by later traditions.  Whatever happened, it was not long before the Roman cavalry gave in; from there on it was a slaughter as the retreat was hampered by the confined space. On the Roman left the battle was far less decisive: here Varro faced the light Numidian cavalry which did not have the strength to charge. Instead, the two were content with simply holding each other down as they awaited the completion of their own objectives: the Numidians awaited the arrival of Hasdubral while Varro simply needed to hold down the enemy cavalry as the infantry won the battle. Livy’s story of the 500 Numidian deserters betraying the Romans is most likely a later invention.

With the flank broken, Paullus now moved to the center where the battle was focused. The advance of the massive Roman army must have been slow and awkward due to the inexperience of the body, it was probably a while before it clashed with the Carthaginian body. As the distance between the armies narrowed, both began to use their missiles: neither one succeeded in producing serious casualties, rarely did they. Both armies would have started shouting louder and louder as they neared, since it is at this anxiety and fear was at its peak. Finally, the center of the Roman line met with the Spanish and Celtic center.

One of the great Roman stereotypes of the barbarian is the lack of endurance. He is typically described as ferocious, impetuous and easily defeated if met by stern resolve. Cannae is surely one of the many cases where the stereotype is broken: “…the infantry became engaged, and, as long as the Gauls and Spaniards kept their ranks unbroken, both sides were equally matched in strength and courage..”(8). For all their tenacity, the Gallo-Iberian line was too thin and lacked reserves; the Roman had three lines worth of reserves. The Romans continued to gradually gain against their adversary until Hannibal’s center finally collapsed. The casualties his center suffered is a testament to its fortitude.

With the enemy center now collapsed the Roman generals must have thought victory was imminent. They poured in all of their reserves into the line to solidify their victory. The organization of the army, already undermined by its size, was completely sacrificed in order to achieve the breakthrough: maniples dissolved into individual pockets led by various officers. The Roman army’s greatest advantage was now lost. Polybius gives us the best description of what occurred next.

The Romans…going in pursuit of these troops, and hastily closing in towards the center and the part of the enemy which was giving ground, advanced so far that the Libyan heavy-armed troops on either wing got on their flanks. Those on the right, facing to the left, charged from the right upon the Roman flank; while those who were on the left wing faced to the right, and, dressing by the left, charged their right flank, the exigency of the moment suggesting to them what they ought to do.

The Romans had no way of coping with the fresh and well ordered attack on their flanks, their only resistance was in the form of small pockets. The legion's advance was now stopped, allowing the Celtic and Spanish troops to rally and take the offensive.

At the same time Hasdubral chased out the remnants of the Roman right wing, reorganized and hit the rear of the Roman left, still occupied with the Numidians. The force was easily routed and the Numdians was sent out to chase them, Varro fled with his men. Hasdubral followed this with an attack on the enemy's rear. The intermixture of the Roman troops during the advance meant that there was no organized triarii(9) in the rear to halt the Punic cavalry’s offensive. Instead, the cavalry pierced into the mesh that once was the Roman army, destroying what little morale existed. It is at this time that Lucius Aemilius Paullus died fighting with his men; here marks the point between battle and slaughter. 

For the rest of the day the Carthaginians hacked at their defenseless and fatigued adversary. On the Roman part, confusion and terror dominated and many died trying to flee for their lives; others may have wanted to fight, but were utterly isolated and dealt with similarly. The entire army now a blob, the vast majority of the Romans could do little but wait while the screams and shouts came ever closer. Hannibal’s men would have continued until they were wholly exhausted. What remained of the Roman force was now able to flee.

In the Aftermath

The remnants of the Roman army fled in various directions. According to Livy, 7000 to the smaller camp, 10000 to the larger one and 2000 to Cannae. The latter were surrounded by Carthalo in the unfortified village. Varro managed to escape with a body of cavalry, but nearly 80 senators, 29 military tribunes and many ex-consuls, praetors and aediles were not so lucky. The total death count was around 50,000 men with around 4500 captured; thousands more would be added from the later capture of the Roman camps. Hannibal suffered around 5000 casualties and thousands more injured, the number was over twice the 5% death toll usually suffered by a victorious army(10). This was no easy victory.

Varro made it to Venusia while the largest body of survivors retreated to Canusium, where they were cared for by the inhabitants. They were led by a number of tribunes, among them the younger Publius Cornelius Scipio, future ‘Africanus’. Here, a story relates that when news spread that a group of nobles were planning to sail to another country and abandon the Republic, Scipio arrested the ringleaders and forced the rest to give an oath never to abandon Rome or speak of doing so. When Varro learned of this body he moved to Canusium. Eventually, two fledgling legions were formed of the Cannae survivors.

With such a poweful victory now in his resume, Hannibal could finally sit back.  It would only be a matter of time before Rome sent out an embassy to sue for peace, or before Rome's allies abandoned their now crushed occupier. Maharbal, one of the cavalry leaders, is said to have chastised him for this decision, urging Hannibal to make an attack on Rome, with the cavalry moving ahead; when Hannibal refused, Maharbal replied with the timeless charge: “Vincere scis, Hannibal; victoria uti nescis” (“You know to win a victory, Hannibal, but not how to use it”) (11). Maharbal’s proposal that Rome could be reached within five days is absurd considering the 400 km between the city and Cannae, however fast Hannibal could move when necessary, an average of 80km a day is impossible, especially considering the utterly exhausted state his men were in. Instead, he chose to send representatives to negotiate peace.  In the immediate aftermath of this grave defeat, one has to wonder whether Rome even had the will to resist Hannibal at all. 

As often happens, rumor of the battle pierced before the actual news. Having no contact with the survivors, the city of Rome naturally assumed that the entire field army was destroyed, a belief not far from reality. A rage of panic and mourning spread throughout the city, we can image hearsay diluting any truth that made its way into the terrified populace. This was finally checked when Varro sent letters to the senate informing them of the survivors; nevertheless, the reality was still bleak. The senate quickly checked the mourning and took care to amend any insult to the gods: two vestal virgins were buried alive under the charge of breaking their oath of chastity; while two Gauls and two Greeks were buried alive in the Forum Boarium, one of the rare cases of human sacrifice in Roman history. At the same time a new dictator was appointed, Marcus Junius Pera, with Tiberius Sempronius Gracchus as Magister Equitum (Master of the Horse). Marcus Claudius Marcellus replaced Varro and new levies were held. The SPQR underwent one of the greatest recoveries of antiquity; one rarely rivaled in all of history.

When the Carthaginian delegates arrived they found the Roman senate unwilling to even meet with then. Carthalo, who was sent as an emissary, was met by a lictor outside the gates of Rome and told to leave Roman territory by nightfall: they would only negotiate should Hannibal admit absolute defeat. As for the prisoners, Rome would not pay the ransom and nor would it allow individual families to pay it under the threat of banishment. Rome would not allow its citizens to feed its enemy.

This reaction to Hannibal was unprecedented: no other power in antiquity functioned in such a way. The citizenship exclusivity and resource limitations of ancient states meant that wars were resolved quickly lest it drain the economy. Rome’s ‘empire’ was not modeled after such states, which often treated the conquered as subjects; rather, Rome absorbed those it conquered and thus expanded its resources many times over, allowing it to survive such disasters. Hannibal was ill prepared to deal with such an opponent. All of this rendered the victory at Cannae to be nothing more then a tactical victory.

Main Sources

·        Polybius, The Histories of Polybius, 2 Vols., trans. Evelyn S. Shuckburgh (London: Macmillan, 1889)

·        Livy, The War with Hannibal, trans. Aubrey De Selincourt (New York: Penguin Classics, 1972)

·        Appian, History of Rome, trans. Horace White (Cambridge: Harvard University Press 1982)

·        Goldsworthy, Adrian, Cannae (London: Cassell & Co., 2001)


1.      For Schlieffen and Cannae see Holmes, Terence. ‘M. Classical Blitzkrieg: The Untimely Modernity of Schlieffen’s Cannae Program’. Journal of Military History, 67.3 (2003) pp. 745-771

2.      Interregnum (“between king”): Interreges are picked from the leading senators to hold a comitia (assembly) for the election of new consuls. The use of the interrex seems to fade during this period.

3.      Novus Homo (“New Man”):  A man, mostly of low plebian origin, who is the first in his family to achieve the senatorial status, or, more importantly, a consulship.

4.      For more on the senatorial debates during the interregnum see Twyman, Briggs L. ‘Consular Elections for 216 B.C. and the Lex Maenia de Patrum Auctoritae’. Classical Philology (1984) pp. 285-294. Much shows that Varro had more Patrician backing then Livy is willing to admit.

5.   Livy.XX.36. However, he does mention the fact that lower numbers have been given by different contemporaries. Some historians used this as an excuse to lower the number since there is a tendency in the ancient world to exaggerate figures. This is generally not accepted. See: Goldworthy, Cannae 66.

6.      Modern Ofanto: The river moves from Campania into Basilicata and discharges into the Adriatic via Apulia. Since its flow has diverted often there has been a lot of speculation over where exactly the battle was fought.

7.      Exact numbers are impossible to ascertain since we do not get the contingent figures. Goldsworthy, 110

8.      L.XX.47. For a reconstruction of Roman battle see Sabin, Philip.‘The Face of Roman Battle’. Journal of Roman Studies, Vol. 90. (2000) pp.1-17

9.      Hastati, principes, triarii. Respectively the first, second and third line of the Republican legion. Unlike the hastati and principes, the triarii were armed with a long spear which they likely carried underhand. “Ad triarios rediisse”(“Falling on the triarii”) was a common expression signifying a last desperate stand.

10.  Sabin, Philip. ‘The Face of Roman Battle’. Journal of Roman Studies, Vol. 90. (2000) pp.1-17. Livy puts the figure at 8000(L.XX.52)

11.  On the quotation and its history see Hoyos, Dexter. ‘Maharbal’s Bon Mot: Authenticity and Survival’. The Classical Quarterly, New Series, 50.2. (2000) pp. 610-614. It has been argued that Marharbal simply wanted to catch the Romans by surprise in their moment of shock. Under such circumstances, a 5 day march of 400 km seems plausible. See Hoyos, B.D. 'Hannibal: What Kind of Genius'. Greece and Rome, 2nd Series, 30:2 (1983) pp. 171-180