The brutality of the Roman campaign against the African towns prompted the authorities in Carthage to bombard their commander with orders to join battle. Hannibal refused to be hurried and remained in his camp near Hadrumentum. He knew that his army was weak in cavalry and managed to persuade a relative of Syphax's named Tychaeus to join him with 2,000 Numidian light horse. Scipio was equally concerned that Masinissa should now justify his support by bringing a strong force of auxiliaries to assist the Roman army, and sent repeated messages to him. Finally Hannibal decided to break the stalemate and advanced his army to Zama, five days' march west of Carthage. Pausing there, he sent spies and scouts out to locate the enemy and assess their strength. Three spies were captured by the Romans, and on Scipio's orders they were given guided tours of his camp and told to report everything to Hannibal. It was the sort of stratagem which demonstrated a general's confidence, but it is also possible that the intention was to convince Hannibal that Masinissa had not yet arrived, for Polybius claims that the king rode into the Roman camp on the next day. He brought with him a reinforcement of4,000 cavalry and 6,000 infantry, the latter perhaps including some of Laelius' command. Livy repeats these figures, but believed that the king had arrived before the capture of Hannibal's spies and that their report discouraged the latter. Both authors report that the Carthaginian was eager to meet his young adversary and that the two commanders met for a parley, but it is questionable whether the speeches attributed to them preserve anything of their actual conversation.25
The Roman army was encamped on a hill outside a town called Magaron by Polybius and Naragarra by Livy. As usual it has proved impossible to locate the battlefield with any certainty, although it was clearly somewhere to the west of Zama. The Roman position was good with close access to a plentiful water supply. Hannibal advanced and camped on another hill just under 4 miles away. It was a stronger position but lacked a good water supply. On the next day the commanders met for their parley and it was on the second day that the armies marched out to fight. Such a swift confrontation, without the usual days of skirmishing, indicates the eagerness of both commanders for battle. The willingness to fight immediately created an impression of confidence in the outcome which could have an adverse affect on the opposing side's morale.26
We do not know the size of the opposing armies, but it is probable that the Romans had fewer infantry and significantly more cavalry than their opponents. Appian gives figures of 50,000 men for Hannibal's army and 23,000 foot and 1,500 horse plus Masinissa's Numidians for the Romans, but his account of the battle is generally unconvincing and needs to be treated with caution. Scipio massed the Roman and Italian cavalry on the left wing, putting Laelius, who was now serving as his quaestor, in charge. Masinissa's 4,000 Numidian light cavalry formed the right. In the centre were the legions and alae in the usual triplex acies with one slight variation. Instead of stationing the maniples of principes to cover the intervals between the maniples of hastati, they were drawn up directly behind them, with the triarii in turn behind them. This created a series of wide lanes running right through the Roman formation. Groups of velites were stationed in these gaps, probably in skirmish order, although it is possible that initially they were formed up to conceal the nature of the Roman deployment. These men were given specific orders to deal with the elephant attack which it was clear would open the battle. More than eighty of these beasts formed a line in front of the Punic army. Hannibal divided his cavalry between the two wings, the Numidians facing Masinissa and the Carthaginians and other nationalities opposite Laelius. The infantry in the centre were split into three lines, mirroring the Roman formation. The first line was composed of Ligurians, Gauls, Balearic slingers and some Numidians. This appears to have been the remains of Mago's army brought back from Italy. The second line consisted of troops raised for the defence of Africa, Libyans and a strong contingent of Punic citizens, making a rare appearance as a formed unit during the wars. One tradition claimed that there was also a strong force of Macedonians in this line, but since it would be most unusual for Polybius not to mention the involvement of Hellenic troops this is normally rejected. The last line, held back a couple of hundred yards behind the second, consisted of his own veterans, a mixture of many races nearly all now equipped with Roman armour and shields. The narratives of the battle suggest that they were roughly equal in number to the entire Roman heavy infantry, so perhaps there were between 15,000-20,000 of them.27
The two sides' deployments were very similar and showed just how much the two military systems had learned from each other during the long years of war. This was the first time that Hannibal had copied the Roman practice of keeping the majority of his infantry in reserve. He had always known that the strength of the enemy lay in the close order foot of the legions. Now that he no longer enjoyed the superiority in cavalry which had marked his earlier battles, Hannibal realized that he stood little chance of enveloping the Roman centre as he had done at Trebia and Cannae. The only alternative was to punch straight through the middle of their line. The Roman system of multiple lines gave their determined legionaries great staying power in combat, allowing fresh troops to be fed into the fighting line as the battle drew on and the enemy wearied. The strong force of elephants would first charge straight into the Roman front line, causing casualties and hopefully spreading disorder, as a similar attack had done to Regulus' army in 255. Hannibal's infantry lines could then advance to exploit this confusion, the reserve lines continually renewing the army's forward impetus as fresh troops were fed in. Ideally all three Roman lines would have been committed to the fight before Hannibal's own veterans, who significantly outnumbered the triarii, moved forward to complete the victory. It was not an especially subtle plan, but it was certainly the most practical in the circumstances. Scipio was too able a commander to be outwitted into fighting in unfavourable circumstances in the way that Hannibal had defeated his opponents earlier in the war. More importantly his own army was not as good as the one he had taken to Italy in 218, whilst Scipio's was one of the best trained forces ever produced by the Roman militia system. Hannibal's veterans, experienced and confident both in themselves and in their officers, composed less than half of his total force. His first and second lines were each formed from the remnants of two different armies, as unfamiliar with Hannibal as they were with each other. There had simply not been the time over the winter months to convert these disparate elements into a single army with a clear and homogenous command structure. Therefore Hannibal's deployment had the added advantage of effectively allowing the three different armies composing his force to operate independently. It is notable that whilst Hannibal made a speech to his own men, he ordered two distinct sets of officers to speak to the first and second lines. It was far easier for Scipio to ride along the ranks of his own army, encouraging the men, for, except for many of Masinissa's warriors, his soldiers had served under him for the past three years and army and commander were well known to each other.28
It took several hours for the two armies to march out and deploy, during which time there was only some sporadic skirmishing between the Numidian horsemen serving on both sides. Eventually when both were ready and the commanders had finished making speeches each side raised a cheer and sounded its trumpets in the customary gesture intended to demonstrate confidence and intimidate the enemy. The sudden burst of noise starded the elephants and seems to have caused them to attack prematurely. The far larger than usual number of war elephants suggests that the vast majority had recently been rounded up and were probably poorly trained. On the left a number of the animals panicked and stampeded back through the ranks of their own cavalry. Masinissa spotted the opportunity and led his men forward in an immediate attack on Hannibal's Numidian allies, routing them almost immediately. The remainder of the elephants surged forward against the Roman infantry. It must have been a truly intimidating sight as so many of the huge animals bore down on the waiting Romans. The velites skirmished forward, throwing showers of javelins at the oncoming beasts. Wounded, or their crews killed, the elephants became even more inclined to panic. Some velites fell and others fled back to shelter behind the formed maniples of hastati, but few of the elephants charged into the heavy infantry. Instead most of them stampeded through the lanes deliberately left in the Roman formation. Later they were disposed of at leisure in the rear of the army. Some on the right swerved towards the Roman cavalry, but changed direction again when they were greeted with a volley of javelins. Now completely out of control, they burst back through the Carthaginian cavalry. Laelius then copied Masinissa's example and charged forward against the disordered enemy horse, putting them to flight.
The elephant attack had failed and Hannibal had lost both of his cavalry wings in the opening stages of the battle. However, both Laelius' and Masinissa's horsemen had chased the enemy off the battlefield, driving them hard to prevent any attempts to rally. This meant that the Roman cavalry would be unable to intervene in the main action for some considerable time. It has occasionally been suggested that Hannibal deliberately ordered his cavalry to flee to draw the numerically superior enemy horse away from the action, but this is certainly incorrect. The Punic cavalry would have been more useful to their commander if they had remained and kept Scipio's cavalry busy for as long as possible. Our sources were convinced that it was not so much the numerical superiority of the Romans and Numidians, but the confusion caused by the stampeding elephants which produced the rapid flight of Hannibal's cavalry.29
The first two lines of Punic infantry had probably begun to advance as soon as the elephants attacked. The third line remained stationary under Hannibal's direct orders. The Roman foot went forward to meet them once the elephants had been repulsed or passed through their lines. As usual both sides advanced noisily, the men cheering and trumpets blaring. Polybius mentions again the Roman custom of banging their weapons against their shields, the principes and triarii in reserve urging on the hastati, and contrasts this with the discordant yelling of the many races in the enemy ranks. This was a theme as old as Homer's Iliad, which in fact Polybius quotes in this passage, repeated often in narratives of the Greek victories over the Persians. Yet the whole point of shouting during the advance was to frighten the opposition and to encourage yourself, and many sources testify to the importance of noise and appearance in deciding the outcome of encounters. The Romans may in fact have gained some advantage over the enemy in this way, although if so, it was not an overwhelming one for the first Punic line put up a very good fight. Polybius' text is slightly corrupted at this point, but he appears to have said that the two sides did not spend much time throwing missiles at each other, but rapidly charged into contact, a sign of their enthusiasm.30
Mago's old army attacked with great enthusiasm, inflicting significant losses on the hastati. After each lull in the fighting they renewed the combat, but gradually their charges slackened, whilst the Romans kept steadily pushing forward. Livy claims that the legionaries used the bosses of their shields to punch at the enemy, unbalancing them. Standard practice in the later, professional army, this was harder to do with the heavy shields of this period, which seem to have weighed over 20 lb (about 10 kg). Theprincipeskept up close behind the front line, but do not yet seem to have joined the fighting. The Ligurians, Gauls and others in the Punic first line received littie aid from their supports, the second line of Libyans and Carthaginians hanging back. The failure of the two lines to co-operate properly is probably another indication of the lack of unity in the disparate elements of Hannibal's army. Our sources even claim that fighting broke out between the two lines as men from the first attempted to retreat through the second. It is possible that Hannibal had issued instructions to the reserve lines not to let fugitives through their ranks, as he had with his veterans. Some sort of fighting line was established, merging elements of the first and second lines. For a while the advance of the hastati ground to a halt. Polybius implies that at least some of the maniples of principes were then fed into the fighting and that the injection of these fresh troops into the combat renewed the forward impetus of the Roman infantry, putting the enemy to flight. The hastati, their order gone after two hard combats, surged forward in pursuit, hacking down at the enemy as they ran. This was always the time when most casualties occurred and it was particularly difficult for men wounded in the legs to escape.31
Hannibal's veterans refused to break their ranks and presented a levelled row of spear points at their comrades fleeing towards them. Officers bellowed at the men to go around the flanks of the third line and rally behind it. At least some of the units may have recovered and formed up to reinforce the last reserve of the Punic army. Hannibal's veterans were intact and apparently unperturbed by the rout of the other mercenaries and citizen troops. However, it is possible that the flight of the forward lines made it impossible for Hannibal to send the third line forward in a counter-attack against the Romans, who were now in some disorder. The hastati were for the moment out of control, chasing the men who had inflicted considerable losses on them earlier in the day, whilst even theprincipes had fought a short combat and lost some of their order. An attack might have been able to profit from the confusion in the Roman lines. However, between the Romans and the veterans the ground was strewn with corpses and slick with blood, difficult ground for a formation to move across whilst retaining its order. Hannibal may have preferred to remain where he was, the ranks of his men in perfect order, and allow the Romans to come to him, hoping that in their current state their advance would be improperly coordinated and lack power.32
Scipio's army then gave another proof of its high level of discipline, not by carrying out a complex manoeuvre, but by the even more difficult task of reforming in the middle of a battle. Trumpets sounded to recall the hastati from their pursuit. In the time taken for these men to come back and form up once more, the wounded were taken to the rear and other troops given some time to rest. Scipio, and probably his officers of all ranks, busied themselves reforming the line. The hastati reformed in the centre, whilst theprincipes and triarii were brought up on either flank. For once the Roman legions reverted to the tactics of the old hoplite phalanx, forming a single dense line matching the enemy's. When ready the Romans resumed their advance, and Hannibal's men came on to meet them. It proved a hard struggle, for the two sides were roughly equal in number and similarly equipped. Some of the soldiers on both sides were veterans with over ten years' service. The Romans were probably more tired, but were confident from their recent defeat of the first and second lines. A prolonged slogging match ensued. In the end it was decided by the return of Laelius' and Masinissa's rallied cavalrymen who returned to the battlefield and took Hannibal's veterans in the rear, making them suffer as they had once made the legions suffer at Trebia and Cannae. It was the final irony of the war that the Cannae legions won Rome's greatest success.
The Carthaginian losses were heavy, 20,000 killed and as many captured according to Polybius. The Romans lost 1,500 men, around 5 per cent of their total if their army numbered 30,000 (and it is unlikely to have been any larger). This was a substantial loss for a victorious army, testimony to the hard fighting, and there is no need to prefer the higher figure of 2,500 given in some later sources. The outcome of the battle was not inevitable, despite the great advantage the Romans possessed in Masinissa's cavalry. Hannibal's basic plan was sound and might easily have succeeded. Had Scipio not arranged his formation to let the elephants pass through between the maniples, then their charge might have inflicted as much damage as a similar onslaught had on Regulus' legions in 255. Hannibal's use of three lines of infantry, with the best troops in the last line, did much to weary the Roman foot, exhausting the hastati and taking the edge off the principes. It was only Scipio's ability as a commander and the discipline and high morale of his men that allowed them to reform and then hold their own in the final engagement. It is impossible to know which phalanx would eventually have prevailed if the Roman cavalry had not returned to take the enemy in the rear. Hannibal's tactics were not intended to surround and annihilate the enemy to the same degree as his earlier victories. He did not need such a complete victory. Now the Romans were the invader with the small, outnumbered army far from their home bases, just as Hannibal had been in the early years in Italy. If Scipio had suffered a clear defeat then it would most probably have meant the end of the African expedition, even if much of his army had escaped.33