Cannae

by Adrian Goldsworthy

  In essence Hannibal hoped to use the Romans’ own strength against them, drawing them in to be surrounded and destroyed. It was a complex plan, contrasting sharply with the brutally simple tactics of the enemy. It also made very heavy demands on both his soldiers and their officers. Hannibal himself, supported by his youngest brother Mago, took up position in the centre with the Spaniards and Gauls for it was vital that these warriors held out as long as possible. The Numidians were led by Hanno according to Polybius and Maharbal in Livy’s account, whilst the vital task of leading the squadrons on the left was entrusted to Hasdrubal. The events of the battle were to demonstrate the great superiority which the Carthaginian army derived from the command structure and mutual trust between leaders and forged by years of campaigning together. In spite of this, the plan was fraught with risks and by no means as certain of success as is sometimes implied in modern accounts.

  Hannibal’s tactics were tailored to the specific conditions of the battle, with the Romans, and especially their infantry, deployed in great depth on an exceptionally narrow front. Over the years some highly fanciful attempts have been made to see this as the fruition of long-held plans, perhaps even based on the naval battle of Ecnomus or first conceived by Hamilcar Barca, passed on to his sons and experimented with at Trebia and Ibera in 215. There is no reason to believe that either Hamilcar or his capable sons attempted to conform rigidly to previously conceived plans. It is worth considering when Hannibal decided to form his army in this way. The decision to advance the centre of the Spanish and Celts may have been made on the spot, late in the stage of the army’s deployment, but the concentration of all of his heavy cavalry on the left and the positioning of the Libyan foot on the flanks must already have been decided upon before the army marched in its deployment columns out of camp. Organizing the army and issuing orders so that each contingent knew where it was supposed to be took time. It seems unlikely that Hannibal could have devised these complex tactics and the means of implementing them after he had seen the Romans begin to march out of camp and cross the river on the morning of 2 August. There was no reason for him to have formed his army in this way and on such a narrow frontage when he offered battle in the plain north of the river. Had he known that the Romans were planning to form on the narrow plain between Cannae and the river then the lack of space would have given a fairly clear idea of their likely deployment. This raises the intriguing possibility that the Carthaginians had seen Roman officers looking at the ground on the previous day–a highly likely activity if they were considering fighting on it. If this is right then it would further support the idea that Paullus, who was in command on 1 August, was far less reluctant to fight a battle than our sources suggest. In some way Hannibal does seem to have known or guessed how and where the Romans would fight and devised his plan accordingly, or perhaps his soldiers and officers were so superior to the enemy that he was able to react to the Roman plan and still form up within the time taken for the great enemy host to deploy.21

  THE BATTLE

  Opening Moves

  We do not know how long it took for the two armies to march from their camps and deploy for battle, but at the very least it must have taken several hours. Throughout this process, each army’s officers, especially the Roman tribunes who seem to have had a particular responsibility for overseeing the army’s deployment, needed to be very active, closely regulating the columns and then ensuring that each unit ended up in the right place and correct formation. At the end of this process, something like 126,000 men and at least 16,000 horses were packed into a few square kilometres of the narrow plain between the Aufidius and the high ground near Cannae. In summer the Apulian soil is dry and the tread of so many feet and hoofs must have thrown up great clouds of fine, sandy-coloured dust to be whipped around by the sudden gusts of the Volturnus wind. A fragment of the Roman poet Ennius, who composed his epic verse history of Rome not long after the Second Punic War, appears to refer to the dust of Cannae.22

  Each army marshalled its line behind a screen of light infantrymen and it was these troops who opened the fighting, closing to skirmish with each other. Javelins could be thrown perhaps as far as 30–40m, although their effective range is likely to have been less. Slings and bows–and there may have been a few archers at Cannae though none are specifically attested–had a range of nearer 200m, but it is much more difficult to estimate their effective range. The distance and accuracy of fire was determined far more by the skill of the individual slinger or archer than by the technological limitations of his weapon. Unlike firearms, where the missile is projected by chemical energy, a sling or bow transfers the physical strength of the operator to its projectile. Skirmish combats in this period were conducted at ranges of less than a few hundred metres and usually considerably closer. Most battles in the classical world began with such encounters, but these were very rarely described in any detail in our sources. Cannae is no exception, and we are simply told that the light infantry screens met without either side winning a significant advantage. In ideal circumstances skirmishers were supposed to drive back their opposite numbers and then begin to weaken the enemy’s main line, but such successes were exceptionally rare. Even those close order troops who lacked body armour or helmets usually carried large shields which gave very good protection against thrown javelins, arrows or sling stones. It was also extremely dangerous for the light troops to get too close to a formed line for they were highly vulnerable to a sudden charge, especially if unsupported by close order infantry or cavalry of their own.23

  It is improbable that many casualties were inflicted on either side during combats between skirmishers. Thrown and shot missiles could be delivered with accuracy and some force, but were also highly visible in flight–this was also true, though to a lesser extent, of sling bullets–and therefore comparatively easy for the target to dodge or catch on a shield. Skirmishers operated in a very loose order, with wide gaps between men to ensure that they could easily move to avoid an incoming missile. Even if a man was wounded, and the vast majority of injuries caused by such missiles would not have been fatal, then the distances involved usually ensured that he could be carried away to the rear by his comrades. Skirmish fights seem to have been able to go on for several hours, or even all day, with very few men on either side being killed and no clear result. This is a little difficult for us to imagine, although very similar to some of the long-range musketry duels of the eighteenth and nineteenth centuries AD. Modern studies suggest that relatively few soldiers, even in the best trained units, actively aim at and seek to kill the enemy in combat, most firing their weapons wildly and some not even firing at all. Certainly the ratio between the number of rounds fired and the number of casualties inflicted on the enemy in the well-documented combats of the last few centuries has been staggeringly low, usually at least several hundred to one. It is unlikely that, in the pressure of combat when the target was firing back, the archers, slingers and javelinmen of the ancient world did much better. The loose and fluid formation employed by skirmishers, where there were no set places in rank or file and each man was allowed great freedom to advance and retire at will, made it difficult to force men to fight properly, for it prevented an officer and his comrades from knowing precisely what a man was doing. A minority of soldiers went close to the enemy and sought to make use of their weapons as effectively as possible, inflicting most, if not all, of the casualties. The majority did enough to appear eager, periodically going forward to perhaps within extreme range of the enemy and throwing or shooting a missile, but being more concerned to avoid being hit themselves than to harm the enemy. A minority probably stayed as far in the rear as possible, rarely if ever coming within range. The tentative nature of the fighting between the scattered skirmishers and the ease of avoiding missiles whose flight was readily visible help to explain the indecisiveness and low number of casualties in such encounters.24

  According to our estimates for the size of the armies at Cannae, Hannibal had at least 8,00
0 light infantryman and the Romans perhaps as many as 20,000. It is distinctly possible that the first figure is too low and the second too high, but even so the Romans ought to have had a significant numerical advantage, and we need to ask why this does not seem to have brought them more success. One reason might be that when, as discussed above, only a minority of soldiers fought effectively sheer numbers were not of decisive importance. Another possibility is that the battlefield was too small for so many loose order troops to deploy and made it impossible for the numerically superior Romans to outflank their opponents. Probably the most important reason was the greatly superior quality of Hannibal’s light infantry. These included the renowned Balearic slingers, Spanish caetrati (warriors with light equipment and the small round shields from which they derived their name) and, probably, Libyans and Numidians. The combination of slings and javelins made the Punic skirmishers effective at both long and short range and they seem to have been well-trained, specialist troops. In contrast the Roman velites consisted of those too young to fight with the heavy infantry or too poor to afford the necessary equipment. Nearly all were armed with javelins, although it is just possible that there was also a small contingent of archers, but they do not appear to have received much training for their role. At Telamon in 225 BC the velites had performed very well, although significantly they were not opposed by many enemy light troops on this occasion. In the early second century BC Roman velites proved themselves markedly superior to the skirmishers in eastern armies, displaying a notable willingness to close and fight hand to hand. There was no trace of similar aggression in the early years of the Second Punic War. Some have suggested that it was only after the legions changed the equipment and training of their light infantry in a major reform in 211 that these began to become effective troops, but there is no good evidence for this. Far more probably it was a case of the greater experience derived from service in the war with Carthage which produced the high quality velites of the early second century, and we should note that in every respect the legions fielded in these years were far better than their predecessors. In 216 the Roman light infantry were mostly inexperienced and had received little or no training.25

  The Cavalry Clash on the Wings

  At Trebia Hannibal had withdrawn his light infantry once they had driven in their Roman counterparts, and sent them to support his cavalry, adding to the discomfiture of the already tired and outnumbered Roman horse. It is possible that he did the same at Cannae, for later in his narrative, Livy tells us that ‘at the beginning of the battle he [Paullus] had been seriously wounded by a slingstone’, although this was not to stop him from continuing to lead his men. Polybius does not mention this and in fact says that, when Paullus left the defeated right wing and went to join the struggle in the centre, he was unwounded. Perhaps he meant that the consul had not suffered an incapacitating wound, which might reconcile the account with Livy’s, or he had simply not heard this tradition, but it is also possible that the story was a later invention intended to add to the already heroic character of Paullus. Ultimately we cannot say precisely what happened to the Punic light infantry, or indeed the Roman velites, after each screen had withdrawn behind their main lines, but it seems probable that they continued to act in support of the formed troops.26

  What is clear is that very early in the battle, and certainly before the main lines of infantry had clashed, Hasdrubal led his Spanish and Gallic horsemen in a direct charge against the Roman cavalry on the right. Normally cavalry combats were fast moving and fluid affairs. In a charge, the faster a squadron went the more its formation dissolved as faster horses with better riders outstripped the lesser mounts and less skilled horsemen and, even more importantly, the minority of bolder soldiers naturally pushed ahead of the majority of more timid men. Deep formations, with cavalry as with infantry, made it harder for men to run away, but it was very difficult to keep in close formation as the speed increased. A successful charge, especially when the victors gave in to their natural exhilaration and pursued the fleeing enemy, resulted in scattered men and tired horses. If the victors were then themselves charged by a fresh and well-formed enemy squadron then it was very likely that they in turn would flee. In most cases, as with cavalry encounters in the eighteenth and nineteenth century AD, it was comparatively rare for the two sides to cross swords in a prolonged mêlée, since usually one or the other wheeled and fled before contact. Charge and pursuit was frequently followed by flight until the enemy were in turn driven back by fresh reserves and the squadron could reform. Victory normally went to the side which kept in hand a formed reserve on fresh horses after all the opposing cavalry had been committed.

  The fighting at Cannae did not conform to this pattern and Polybius tells us that there was none of the normal ‘wheeling about and reforming facing the original direction’. According to Livy this was because the fighting occurred in such a confined space, between the river and the flank of the Roman infantry, making it impossible for either side to outflank the other. Instead the Carthaginians attacked head on into the Roman cavalry, and the ensuing combat was described by Polybius as ‘barbaric’, clearly in the more general sense of the word as particularly brutal and unsophisticated rather than implying tactics peculiar to the tribal peoples. He says that many men dismounted and fought on foot as infantry. Livy’s account is similar and he claims that, once the two sides had met, horsemen began to drag their opponents bodily from their seats. This was not the first occasion in the Second Punic War where our sources claim that cavalrymen dismounted to fight on foot, as Polybius and Livy both state that many riders had done this at Ticinus. It used to be thought that the ancient cavalryman’s lack of stirrups gave him the most precarious of seats and as a result made him likely to fall off if he engaged actively in hand-to-hand combat. Recent trials with reconstructions of the four-horned saddle, probably already in use with all the horsemen at Cannae apart from the Numidians, have shown that in fact this provided a very secure seat and allowed a rider to deliver a range of blows, leaning to either side without losing his balance. The horsemen of this period were probably no more likely to fall off during a combat than cavalrymen equipped with stirrups. It was therefore not necessity that persuaded cavalrymen to fight on foot.27

  Plutarch tells the story that Paullus’ horse was wounded and the consul forced to dismount. His staff quickly followed suit and then all the rest of the Roman cavalry, assuming that this was a general order, also got off their horses. Seeing this, Hannibal is supposed to have said that the Romans might just as well have handed themselves over to him in chains like captives. It is not altogether clear to which phase of the battle this anecdote refers, although most probably it concerns the initial fighting on the Roman right wing. Livy tells much the same anecdote, but in this version it was weakness due to his own wounds which prevented the consul from staying on his horse and made both him and his cavalry bodyguard dismount. This occurs much later in the battle and assumes that at least some of the Roman cavalry were not swept away in the rout of the right wing and continued to follow the consul. Appian mentions another tradition which had Paullus dismounting near the end of the battle to fight to the death on foot with a group of survivors. The reliability of any of these stories is very difficult to judge, and the tale of the Roman cavalry accidentally putting themselves at a disadvantage by dismounting may simply have been a Roman invention to excuse their defeat.28

  These stories imply that the decision of some Roman cavalry to fight dismounted was either a mistake or a sign of desperation. As Hannibal’s supposed comments make clear, it made little sense for cavalry to give up the mobility which was their chief advantage. What is clear from our sources is that the fighting between the Roman and Carthaginian cavalry was especially fierce and far less fluid than most cavalry combats. The Greeks and Romans associated determined, static fighting with foot rather than horse, and it is just possible that an account stating that the combat was more like an infantry than a cavalry mêlée is the sour
ce of these passages. Yet all our sources imply that the Roman cavalry did not advance any significant distance to meet the oncoming Gallic and Spanish horse and that their posture was essentially defensive. Cavalry have never been well suited to holding ground, for their advantages lie in speed and mobility. Unless very densely packed indeed and especially determined, a stationary mass of cavalry was always inclined to stampede to the rear when charged by enemy horse. There were many occasions in the ancient world when blocks of infantry were interspersed with cavalry squadrons. The foot provided firepower and, even more importantly, solid shelter for retreating squadrons to rally behind. It may be that at Cannae, some or all of the Roman horsemen were dismounted to act in this way or perhaps some detachments of ordinary infantry were interspersed with the cavalry squadrons, giving a stability to the wing which cavalry on their own would have lacked.29 The Romans needed their cavalry wings to stay in place for long enough to prevent the Punic cavalry from threatening the main assault by the legions in the centre. The Carthaginian cavalry was known to be better than their own horse and, as the enemy deployed, it must have been clear that the Romans were heavily outnumbered on this wing. Mixing mounted with dismounted men offered the prospect of delaying a defeat which probably seemed inevitable, so that it could not affect the eventual outcome of the battle. If this was the consuls’ plan, then it failed.