Cannae Page 7
LOCATING THE BATTLEFIELD
It is rare for the precise location of any battle fought in the classical world to be known with certainty. Literary style was important to ancient historians and too much topographic information was likely to overburden any narrative. As a result, even accounts written by senior officers who were present at a battle mention few geographical features. The campaigns in Italy from 218 to 216 BC are described in some detail by our sources and it is usually possible to determine the general area in which a battle occurred. It is then a question of attempting to relate the snippets of information provided in their accounts of the battle to the terrain in this area today in order to locate the battlefield. Most useful are those major geographical features which are unlikely to have changed in the last twenty-three centuries. Usually there are several sites in the right area which could conform to the ancient sources. The probable size of the opposing armies, their tactical systems and the objectives of each side in the campaign itself provide the context in which we must try to judge on which of these sites the battle is most likely to have occurred. This is an uncertain process, inevitably relying on many guesses and impressions, and as a result it is unsurprising that there is a broad range of opinions concerning the site of most battles. Cannae is no exception to this.
The location of the town of Cannae itself on the line of hills south of the River Aufidius (Ofanto) is one of the few certainties, even if the Roman remains there in fact date to a later period. We know from our sources that the Roman army had constructed two camps. The larger camp lay on the side of the river from which the Roman army had approached Cannae and faced Hannibal’s second encampment. The smaller camp was on the other side of the river, about a mile (1.6km) from the main position, and even further from the Punic camp. The battle was fought on the same side of the river as the smaller camp. Polybius tells us that the Roman line was formed with its right flank resting on the river and correspondingly that the Punic left was also anchored on the Aufidius. The Roman line faced south, the Carthaginians north, so that neither side suffered the disadvantage of fighting with the sun in their eyes. Other sources repeat a Roman tradition that their soldiers were hampered by a strong wind blowing towards them. Although doubtless exaggerated, the prevailing wind in this area is the hot Volturnus, which blows in very strong gusts from the south-west, again suggesting that the Romans faced south or south-west. The Greek historian seems to have believed that the River Aufidius flowed from south to north. In fact it runs more south-west to northeast, but meanders considerably. The general direction of the river’s flow cannot have been any different in the third century BC, but its actual course is far less clear. During the last century the line of the Ofanto has changed on numerous occasions, sometimes even varying from year to year. The contours of the shallow valley through which it flows impose a northernmost and southernmost restriction, but in places this would still permit a variation of several kilometres. As a result, one of our few fixed points on the battlefield proves to be far less certain than we might like.4
So much has been written about Cannae that it is unsurprising that the site of the battle has proved one source of major controversy. In many cases arguments have focused on minor details, but other disputes have been much deeper. The most fundamental question is on which side of the river the battle was fought, since this determines our understanding of the orientation of the battlefield. In recent years very few scholars have argued for a location on the left, or western bank, but in the past a number of eminent scholars have advocated this view, notably Hans Delbrück and Konrad Lehmann. If the battle was fought on the left bank, then the Romans–given that their right flank rested on the river–must have formed up facing towards the sea. There are several problems with this. In the first place it is very difficult to see how Polybius can have believed that the Roman line was facing south, even with his misunderstanding of the river’s orientation. Secondly, for the Romans to have been camped to the west and Hannibal to the east, nearer the sea would suggest a very different build-up to the battle to the most obvious reading of our sources. It is hard to see how the armies could have ended up in this position if the Romans had followed Hannibal to Cannae from the area around Gerunium. Advocates of this view sought explanation in the problematic chronology for the campaign mentioned in the last chapter. If Hannibal left winter quarters at Gerunium when the harvest became available in early June and the battle was not fought until 2 August, then there was plenty of time–nearly two months–for more manoeuvring than is described by our sources. It was possible for Hannibal to have crossed the Aufidius and raided more widely in Apulia, before turning back north, or north-east, to seize Cannae. During this expedition he was followed by the Roman army which kept to the high ground and avoided contact. Only when the consuls had joined did the Romans choose to close the distance and a battle occur. Adherents to this cause suggest that the consuls deliberately chose a narrow battlefield west of the town of Cannae and north of the river, believing that this would protect their flanks from the superior Punic cavalry. They add that the fact that Roman fugitives from the battle gathered at Canusium would make far more sense if their army had deployed to the west of the Carthaginians.5
Whilst it is just possible that our sources skimmed over more than a month of operations and that the battle occurred in this way, this does seem unlikely. It is also difficult to see what useful purpose Hannibal would have served by marauding about southern Apulia. His aim in this campaign was to bring the Roman army to battle and to destroy it. The reluctance of the proconsuls throughout the winter to risk serious engagement and their care to follow him at a safe distance when he finally left Gerunium must have made it clear that there was little chance of joining battle until the new consuls arrived. With the supplies captured at Cannae, and the ease of foraging in the surrounding area, there was really no need for a mobile campaign further south. Hannibal had already demonstrated the Romans’ inability to prevent his going wherever he wished. The ability of the Roman legions at Trebia to retreat to Placentia even though the enemy army lay in between suggests that we should be cautious about making too much of the routes taken by fugitives. In addition the terrain to the north of the Aufidius fits rather better our sources’ description of the Roman march towards Cannae across open country than any possible route from the south-west. On balance, it is far more likely that the battle was fought on the right, or southern, bank of the Aufidius and that the Romans had their backs to the sea and faced roughly south-east. In all of the chapters of this book I have assumed that this was the case and that therefore the larger Roman camp was on the left bank and the smaller camp on the right.
In recent years the River Ofanto has tended to run fairly close to the line of hills on which sits Cannae itself. Many scholars have assumed that there could not possibly have been sufficient space in the plain between the two to accommodate the armies, especially the huge Roman force. J. Kromayer, who assisted by G. Veith, produced in the early twentieth century what is still the classic study of the battlefields of the ancient world, therefore placed the battle to the east of Cannae itself, on the broad plain which slopes very gently down to the sea. This area is certainly wide enough to permit the deployment of nearly 140,000 men. In this interpretation the smaller Roman camp was little more than 4km from the sea and the Roman battle line a short distance in front of it. The left wing of Hannibal’s army would have been fairly close to the edge of the hill of Cannae itself. His camp is unlikely to have been as far to the east as the high ground around San Ferdinando di Púglia, but would have been somewhere on the open plain north of Cannae. There could have been no intrinsic value to such a position apart from the pressure it applied on the enemy by its proximity to their camp.6
However, this battlefield is no less open and suitable for cavalry than the one north of the river where Paullus refused to fight on 1 August. It is difficult to understand why Varro would have made the effort of shifting the bulk of his forces across t
he river to the right bank to fight on virtually identical terrain. Only the Roman right flank resting on the river would have been secure, since the left had no terrain feature to anchor itself upon. In addition the slope, although gentle, would have placed the Romans at a slight, but not insignificant disadvantage. If the Roman army had decided to fight in this position on 2 August then the criticisms levelled at Varro would seem to be valid, for this area offered far more advantages to Hannibal’s cavalry than it did to the Romans. Just about the only reason why the consul might have chosen to move to such a position was an urge to challenge the enemy’s dominance of this bank and the area around the Roman camp which had been threatened by the Numidians the day before. The problems were not solely confined to one side, for wherever Hannibal’s camp lay his columns would have had to march through an awkward little defile around the hill of Cannae in order to reach the battlefield. This would have made his deployment a more difficult and time-consuming process, and a good commander tried to ensure that his troops entered battle as fresh as possible.
Both of these interpretations assumed that the Aufidius flowed on virtually the same line in 216 BC as it did in the early twentieth century. As we have seen, it is in fact perfectly possible that it followed a very different course. Assuming that the Aufidius actually lay much nearer to the northernmost limit, Peter Connolly suggested that the battle was in fact fought north of the line of hills around Cannae on a plain about 2km (c. 1.3 miles) in width. In order to fit such a large Roman force, whose probable frontage he calculated at around 3km (c. 2 miles), into this area, Connolly argued that the Romans deployed at an angle, so that in fact they were close to facing south as Polybius described. This looks a little awkward on his maps, but it should be noted that his estimate for the Roman frontage is too high as we shall see in the next section. It is much easier to fit the Roman army into this position than at first appears. The advantages of this position are obvious. The Romans were able to anchor one flank on the river and the other on the high ground near Cannae, making it impossible for the Carthaginian horse to envelop their line as they had at Ticinus and Trebia. It would make far more sense for Varro to have chosen to offer battle here, rather than simply crossing the river further east to fight in a plain very little different from the one outside the main camp.7
INITIAL DEPLOYMENT
Polybius tells us that the Roman army at Cannae numbered about 80,000 infantry and just over 6,000 cavalry. The figure for the infantry was clearly based on the assumption that there were eight legions of 5,000 foot supported by the same number of allied soldiers. Whether all of the legions and alae were in fact at this theoretical strength on 2 August is questionable, but this figure probably provides a reasonable approximation of the army’s size. If all of the legions had their full complement of 300 cavalry then there should have been 2,400 Roman horse at the battle. The remaining 3,600 or so men were allied cavalry. Normally the allies provided three times as many cavalrymen as the Romans, but this did not occur in the extraordinary circumstances of 216 BC. One of Livy’s sources stated that in this year the allies provided twice as many cavalry as the Romans.8 This may simply have been a rough approximation, but it is possible that not all of the legions were able to recruit the full 300 horsemen and that as a result more of the 6,000 were allied cavalry. Despite the great effort mounted for this campaign, the overall proportion of cavalry in the army was lower than in most other Roman field armies. This may well reflect the casualties suffered in earlier engagements, notably the defeat of Centenius in 217. Another problem which doubtless restricted the number of cavalry with the army was the difficulty of finding so many mounts at such short notice.9
Not all of the Roman army was deployed for battle: 10,000 men were left outside the main camp. As yet the Romans did not know whether Hannibal would accept their offer of battle and transfer his army to the right bank of the Aufidius. Polybius tells us that this was Paullus’ decision and that, whilst they would also guard the baggage, this force was intended to pose a threat to Hannibal’s camp. This would either persuade Hannibal to weaken his army by leaving a strong garrison or, if he did not, allow the Romans to storm the Punic encampment. The loss of baggage, equipment, supplies and camp followers would have been a fatal blow, impossible for Hannibal’s army to recover from if his army failed to win an outright and overwhelming victory. The attribution of this plan to Paullus once again challenges the tradition that he was less aggressive than his colleague. It is unknown who provided this force of 10,000 men, and whether it consisted of detachments from some or all of the units in the camp or of complete units. Some cavalrymen are mentioned in this camp in the aftermath of the battle which, if they were not fugitives, suggests that the covering force included both horse and foot. It has sometimes been suggested that these men were the triarii from the entire army, since 600 men from each of the eight legions and a similar number from the alae would total 9,600 men. There are a few recorded occasions when the triarii were given the task of protecting the army’s baggage, but there is no indication that this was standard practice. Given the aggressive role planned for this force by Paullus, the triarii would not seem the most suitable men to carry this out, for they were not normally used as a strike force. It would also have meant sending some men from the smaller camp which seems rather unlikely. A much more plausible solution would be to see the 10,000 as one legion supported by an ala, but certainty is impossible. Appian, whose account of the battle is generally unreliable and confused, claims that 3,000 men were left as a covering force for the smaller camp. This may have been the case, but this position faced no immediate threat given that the main army was deployed in front of it. It may be that the semi-armed servants and camp followers there were considered sufficient protection, but once again we have no clear information.10
When Varro had united the two sections of the Roman army he formed them into battle formation with the Roman cavalry on the right, the Roman and allied heavy infantry in the centre and the allied horse on the left. Probably, as we have seen, his flanks rested on the river and the high ground around Cannae. There is little or no information on the formations normally employed by Roman cavalry in this period. Polybius, in a criticism of another historian’s account of Alexander the Great’s victory at the battle of Issus, claims that if they were to be effective then cavalry should never be deployed in more than eight ranks. He also states that wide intervals between squadrons were essential to provide them with the freedom to manoeuvre, so that when formed eight deep 800 cavalrymen occupied a frontage of 1 stadium (roughly a furlong), which works out at about 2m (c. 6–7 feet) per horseman. This is probably rather too generous for the Roman cavalry wings at Cannae. At no stage during the battle are either the Roman or allied cavalry recorded as having mounted a serious attack. They were heavily outnumbered and their role seems to have been merely to protect the flanks of the infantry and prevent them from being outflanked by the enemy horse. In such a defensive role there was no need to maintain such large intervals between squadrons or to form only eight ranks deep. In fact some of the Roman cavalry may even have dismounted and fought on foot, although the tradition is rather confused over this point. Allowing 1.5m (5 feet) per horseman and assuming that the 2,400 Roman cavalrymen on the right flank were formed ten deep, then they will have occupied a frontage of 360m and a depth of perhaps 40m. Employing the same calculation, the 3,600 allied cavalry on the left would have needed 540m by 40m.11
As far as we can tell, the Roman legions and allied alae deployed in the normal triplex acies. However, Polybius specifically tells us that Varro ordered two major changes from the normal drill, reducing the gaps between the maniples in each line and making each maniple very deep, so that each was ‘many times deeper than it was wide’. The standard size of a maniple of hastati or principes in a normal legion was 120 men, but we do not know whether there was a standard formation for this unit. Polybius’ statement here, as well as practical utility, suggests that a maniple was not nor
mally formed with greater depth than frontage. If the Romans preferred to have equal numbers in each rank then a formation of twenty men wide by six deep or fifteen men by eight deep would be prime candidates. If each legionary was allocated a frontage of 1m (c. 3 feet) and a depth of 2m (6–7 feet) then the maniple would cover 20m by 12m or 15m by 16m respectively. The scant evidence for the formations of the later professional army suggest systems of drill based upon multiples of three or four, the latter being standard for Hellenistic armies. However, it is possible that the third century BC Roman army had no standard system of drill and that the depths of maniples was determined for each battle by a legion’s or an army’s commanders, as had been the case with most Greek hoplite armies.12
The legions at Cannae were unusually large with 5,000 foot apiece. Polybius tells us that when the size of a legion was increased, the number of triarii always remained the same at 600. The remaining 4,400 men were supposed to be divided equally between the hastati, principes and velites, giving each approximately 1,466 men. This would give an average strength for a maniple in the first two lines as about 146 men. If there were in fact seven legions and seven alae making up the line, allowing for one of each left in the larger camp, this would give 20,524 men in each of the first two lines and 8,400 in the third, a total of 49,448, supported by 20,524 velites. Such a strong force of light infantry ought to have given the Romans a distinct advantage in the skirmishing at the beginning of the battle, and, although there may be other reasons why this was not the case, it is possible that there were fewer velites. We know so little about the internal organization of the alae that it is impossible to say whether in fact these included roughly the same proportion of light infantry as the legions. It is also possible that, as in so many other respects in the 216 campaign, the normal procedures had been modified and the legions were themselves composed differently. In either case perhaps we should reduce the number of skirmishers by several thousand and add these to the heavy infantry. Most commentators on the battle estimate the number of close order infantrymen at around the 50,000 to 55,000 mark, but precision is impossible.13