Zama: The Infantry Battle Revisited

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by Steven James



This hypothesis is an attempt to look beyond the accepted or traditional Polybian(1) interpretation of the Battle of Zama in regard to the events of the Roman and Carthaginian heavy infantry. In doing so the evidence presented will hopefully demonstrate that Hannibal had lost none of his military genius. This article does not cover the cavalry or elephant battles but focuses solely on the heavy infantry. Although this reconstruction includes some assumption and probability, it does remain faithful to Polybius and does not ask the reader to undertake a large stretch of the imagination. The most outstanding issues of the infantry battle to be analyzed and explained are:

  • The number of infantry combatants
  • The failure of the second Carthaginian line to support the mercenaries
  • Hannibal’s positioning of his third line 200 yards behind the second line.
  • Hannibal’s third line lowering their weapons to prevent the second line from interpenetrating them
  • Scipio’s recall of the Hastati and his non-standardized redeployed of the Roman army into a single line

Some of these issues are not fully explained by Polybius, but this is understandable. Polybius’ main source was Masinissa, who commanded the Numidian cavalry at Zama, and having been involved in the pursuit of the Carthaginian cavalry for most of the battle, would not have been aware of the subtle tactical maneuvers been undertaken by Hannibal’s infantry. Even if Polybius had access to more detailed information on the battle, he was not in a position to freely express them as he saw fit. Polybius was a friend of the Scipio(2) family but more importantly a Roman hostage. It is quite possible Polybius voluntarily (or involuntarily) omitted crucial events or outcomes deemed unsuitable by the Scipios. Polybius outlines Hannibal’s strategy as:

"the mercenaries in front with the Carthaginians behind them in the hope of that the enemy would become physically exhausted, and their swords lose their edge through the sheer volume of the carnage before the final engagement took place."

Basically Polybius states Hannibal’s strategy was to wear down the Roman army before engaging his veterans. Gone are any signs of Hannibal’s military genius displayed in his previous battles. No stratagems, no maneuver, just a declaration the battle was nothing more than one of attrition. This is unusual for Hannibal and completely out of character. To understand this we have to remember that Polybius’ account is seen through Roman eyes and because of this we only have a Roman perspective. But can any new outcomes or conclusions be retrieved if we view this battle through non Roman eyes? The answer is yes.

The Number of Heavy Infantry Combatants

Polybius, Livy, Dio, Nepos and Zonaras do not give the actual number of combatants for each army, but when describing the Carthaginian deployment; Polybius gives Hannibal’s first line of mercenaries as 12,000 men. Appian(3) gives Hannibal’s army as 50,000 in total and Scipio's army as having 23,000 infantry. Livy(4) and Polybius’ give reference to Masinissa’s supplying 6,000 infantry and this would place Scipio’s force at 29,000 infantry. Appian describes “attendants armed with darts” as being intermixed with the cavalry, and these attendants could be the 6,000 infantry supplied by Masinissa.

Livy states the two Roman legions (the V and VI) were brought up to their full complement of 6,200 men, a number that is quite feasible. If there were four legions involved each with 6,200 men this gives the total number of infantry who left for Africa as 24,800. Deducting Appian’s total of 23,000 infantry from Livy’s theoretical total of 24,800 leaves us with a discrepancy of 1,800 infantry. This discrepancy could be casualties from two years of fighting in Africa. Deducting the number of Carthaginian cavalry given by Polybius and Livy from Appian’s total of 50,000 gives Hannibal a total of 46,000 infantry. This could be an exaggeration, or Appian has rounded up his figures. The latter seems likely. Both Polybius’ and Appian’s accounts of the speeches made by Hannibal to his men clearly stipulate that the Carthaginian army was superior in numbers to the Roman army. The heavy infantry of both parties have been broken down in the following order.

Scipio’s infantry could consist of: 5,000 Velites 18,000 heavy infantry 6,000 Numidian infantry Total 29,000

Hannibal’s army could consist of: 12,000 Mercenaries 12,000 Carthaginians 18,000 to 20,000 Veterans Total 42,000 to 44,000

From the above, Hannibal’s infantry numbers are 2,000 men short of Appian’s figure. Polybius and Livy give the Carthaginian losses as 20,000 killed, 20,000 captured (total of 40,000) and mentions “a few escaped.” Appian gives 25,000 killed and 8,500 captured (total of 33,500). It is hard to reconcile Polybius’ total destruction of the Carthaginian army with the accounts given by Appian and Nepos.

Appian tells us that: He (Hannibal) took refuge in a town called Thon. Here he found many Bruttians and Iberian horsemen who had fled after the defeat. (Punic Wars VIII. 47).

Nepos writes: At Hadrumetum he (Hannibal) rallied the survivors of the retreat and by means of new levies mustered a large number of soldiers within a few days. (Nepos Hannibal VI).

It is most likely Appian’s casualty figures are more realistic.

Hannibal’s Strategy

Hannibal’s strategic aim at the battle of Zama was for the total annihilation of the Roman army. There was strong division within the Roman senate over the wisdom of invading Africa. A Roman defeat could end all Roman ambition of prosecuting the war in Africa; an outcome that eventuated when Regulus was defeated at the Battle of the Bagradas during the First Punic War. Regulus’ defeat resulted in the First Punic War extending for many more years. Except for naval raids on the African coast, the Romans never undertook another invasion of Africa again.

To totally annihilate the Roman infantry, Hannibal’s battle plan would require a double envelopment maneuver like the one used at Cannae. A battle of attrition that could end with the Roman army able to retreat and then later be reinforced by its navy would be a disastrous outcome for the Carthaginians. Carthage did not have naval superiority and therefore lacked the means of severing Rome’s naval supply line. Hannibal always believed in fighting the war in Italy, a strategy he later tried to encourage Antiochus the Great to undertake. Annihilating the Roman army would guarantee the safety of Carthage and allow Hannibal to return to Italy and continue the war on Roman soil.

Hannibal knew it would be complete folly to repeat the identical deployment used at Cannae against forces that were present at that same battle. His major advantage at Zama was his superiority in infantry, so with these forces he arranged them in such a manner as to exploit their strengths and weaknesses. Hannibal deployed his 12,000 mercenaries in the first line and the second line was made up of Carthaginians and Libyans (probably 12,000). Polybius states the second line was made up of native Libyans and Carthaginians. For reasons unknown, Polybius after his first address of the second line never mentions the Libyans again. Polybius loosely implies the second line was reluctant to fight and this was Hannibal’s reasoning for deliberately placing the Carthaginians between the mercenaries and the veterans. Positioned 200 yards behind the second line were Hannibal’s best troops, his veterans from Italy. Using Appian’s numbers, Hannibal’s veterans possibly numbered up to 20,000 men. Polybius explains that the reason why Hannibal deployed them 200 yards in the rear of the second line was because Hannibal:

intended that they should watch the battlefield from a distance, leaving their strength and their spirit unimpaired until he could draw upon their martial qualities at the critical moment.

Polybius has misunderstood the significant of the veterans’ deployment. At Cannae, the outflanking maneuver by the African infantry was the critical factor in Hannibal’s annihilation of the Roman army and to repeat this accomplishment, Hannibal’s veteran third line would be the critical factor as confirmed by Polybius:

"he (Hannibal) told them (Carthaginian officers) they had sure foundation for victory in the presence of himself and the troops he had brought back from Italy."

The veteran force was purposely positioned some 200 yards behind the Carthaginian infantry so as to prevent the true depth of the veterans’ formation being observed by the Romans. This same tactic of concealment is reminiscent of the tactic used at Cannae. The convex positioning of the Celts and Iberians at Cannae would also have obscured the Romans from seeing the dispositions of the African infantry positioned to the rear on either flank of the Iberians and Celts.

To double envelop the Romans, Hannibal’s third line of veterans, having double the number of men as the first and second line, was probably deployed but not proven with the same frontage as the mercenaries and Carthaginian lines, but the difference being Hannibal’s veterans were deployed in two lines, one behind the other as explained in Aelian’s Manual of Hellenistic Military Tactics(5):

39.6 And being divided into a double-phalanx (diphalangia), it forms the forward-facing “mouth” (the front) with one phalanx, and the rearward-facing one with the other.

The maneuver Hannibal rested his hopes on for annihilating the Roman army was for the veteran second line (organized into two units) to conduct a right or left face turn changing them from line to column formation, then they would march out, half the veteran second line moving to the left and the other half moving to the right of either flank of the veteran first line and surrounding the Roman army while the veteran first line engaged the Romans as outlined in Aelian’s Manual of Hellenistic Military Tactics:

36.4 A march is made either as a “march-in-column” or a “march-in-formation,” or in a single-fronted, double-fronted, triple-fronted, or quadruple-fronted formation.

Once on the Roman flanks and rear, the two veteran outflanking units would conduct a right or left face turn returning them to line formation and then advance on the doomed Romans. It was precarious, as all double envelopments are, but like most of Hannibal’s plans, with disciplined troops it was feasible.

The Role of the Elephants

For his plan to succeed, Hannibal would have to disguise it with a carefully placed stratagem. It is possible, but not proven, that the deployment of his eighty elephants was the stratagem. Hannibal had enough battle experience with elephants to be fully aware of their deficiencies. If they did damage the Romans, all the better, but if they panicked and routed through his first or second line, and caused them to fall back, the more advantageous it was for Hannibal. The real purpose of the elephants was to disguise Hannibal’s intention of double enveloping the Roman infantry by his veteran infantry.

According to Polybius, Scipio’s non traditional deployment of each maniple positioned directly behind the one in front, thereby creating lanes for the elephants to run down, was dictated by his concern about the large number of Carthaginian elephants. Appian also gives an account of Scipio’s efforts to counteract the elephant problem:

But his Numidian horse he stationed on either wings because they were accustomed to the sight and smell of elephants. And as the Italian horse were not so, he placed them in the extreme rear (The Punic Wars VII 41)

Scipio’s deployment as described by Appian shows the same meticulous planning in response to the elephant problem as does Polybius. Did Hannibal also deploy his elephants in front of his army to purposely use history as a psychological ploy to haunt and remind Scipio of Regulus’ defeat by the Carthaginian elephants at the Bagradas? No Roman army since Regulus had faced such large numbers of elephants (eighty versus one hundred). If the elephants were a stratagem, Polybius and Appian’s descriptions of Scipio’s preoccupation with inventing imaginative counter measures to deal with them tell us Scipio had taken the bait.

Polybius’ Battle Description Outlined

The main events as described in Polybius between the Roman heavy infantry and the Carthaginian heavy infantry are:

The first line of mercenaries and the Romans advance to engage with the Carthaginian second line following the mercenaries. Hannibal’s third line does not advance but remains in its original position

Carthaginian second line retreats in a cowardly fashion thereby failing to support the mercenaries who are being pushed back

As the mercenaries retreats some mercenaries turn on the Carthaginians for not supporting them

The second line of Carthaginians counter-attacks the Romans.

Hannibal bars first and second line survivors from entering his ranks.

Scipio recalls the Hastati and redeploys the army

The Heavy Infantry Battle

The Roman and Carthaginian infantry slowly advanced towards each other while Hannibal’s veterans purposely remained stationary. Following Polybius, the mercenaries put up a good fight against the Hastati. The Principes and Triarii, not involved in the fighting, gave the Hastati moral support by cheering them on. The act of cheering one’s comrades in a battle is recommended by Maurice’s(6) Strategikon III.15:

The second line is to wait and see how things turnout, letting out two or three rousing cheers to encourage our troops and discourage the enemy.

Eventually, after repeated charges, the mercenaries were made to give ground, but according to Polybius the second line of Carthaginians now fell back in “cowardly fashion” and failed to support to the first line of mercenaries. First we must examine what is meant by “support.” According to Maurice’s Strategikon II.1:

Supposing that the first line retreats or is pushed back, then the second line is there as a support and a place of refuge. This makes it possible to rally the troops and get them to turn back against their attacker.

Again in II. 13. Maurice states: For during battle, it (the second line) should not be so far behind the first line that it cannot provide support, nor should it be so close that it may get mixed up with it in battle, especially when a lot of dust is being kicked up.

Polybius tells that the mercenaries gave way because they had been abandoned by their own side and Maurice (II.1) throws some light on this when he writes:

First, the troops in the front line will fight more eagerly knowing that their rear is protected by the second line. Second, a man in the first line is not as likely to run away when he knows that many other soldiers are stationed to his rear; that is the second line, and will see anyone deserting his post. In combat this is extremely important.

It appears when the second line fell back it gravely undermined the morale of the mercenaries. As the first line broke some mercenaries vented their anger against the Carthaginian second line by attacking them. But was the second line “falling back in cowardly fashion” as Polybius believes or was the second line purposely falling back (feint retreat) in accordance with a preplanned maneuver? If the second line was purposely falling back it does explain why Hannibal had his veterans positioned 200 yards behind the second line. In pursuing the first line and then the second line, the Romans were drawing closer to Hannibal’s veterans and deeper into his trap as they did at Cannae when the Romans followed up the retreating Iberians and Celts. Again, as at Cannae, for this plan to work, the Carthaginians had to give ground.

The action of the mercenaries turning on the second line indicates the second line had been informed of the overall plan and the mercenaries had not. This explains why the mercenaries believed they were being abandoned. Hannibal quite rightly did not inform the mercenaries of their role in the battle. Had he done so they would have been made aware they were to be sacrificed and rebelled. Another factor to support the fact the second line were informed of the plan was their lack of concern about not being supported by the third line during the opening advance. In principle by not having the third line advance, the second line, like the first line would have felt unsupported, yet there is no evidence to show this was the case.

The moment the mercenaries started to “give ground” was the signal for the Carthaginian officers in the second line to begin falling back. Hannibal knew that once the mercenaries broke, the Hastati, Principes and Triarii as part of their standard battle doctrine would immediately follow up their retreating foe. Polybius’ description of the second line falling back in “cowardly fashion” is misunderstood, especially when Polybius follows up this statement with “when they (the second line) had been bought to bay they defended themselves with desperate courage.” Polybius implies because they had no way out or they were trapped, their cowardice now converts to desperate courage and this desperate courage motivates them to counter-attack. Again it seems Polybius or his eye witness’ misread the significance of the event. In actuality, as part of Hannibal’s plan, the second line had stopped falling back and then deliberately counter attacked the Romans. So far Hannibal’s plan was working. His front line troops were retreating and the Romans were following up and slowly being drawn closer to his veterans.

But then an unforeseeable event occurred that would end Hannibal’s chance of a double envelopment. Polybius’ accounts tells us the second line’s counter attack resulted in some maniples of the Hastati being thrown into confusion and this caused the officers of the Principes to hold firm their ranks so as not to get involved in the confusion. According to Maurice, this seems like standard procedure:

Maurice III. 15: They (the second line) should be very careful not to engage in action prematurely or to get too close to the first line, which could result in confusion and a stupid defeat.

Livy has the maniples of the Principes starting to break up when they saw the Hastati lose formation when pursuing the Carthaginians, and on seeing this Scipio recalls the Hastati. Like Polybius, Livy makes no mention of the Principes being recalled. What is missing from both Polybius and Livy’s account is an accurate reference to the time frame or chronology of events. Combining both Polybius and Livy suggests after the Carthaginian second line counter attacked, some Hastati maniples were disordered but not enough to prevent the Hastati from eventually defeating the Carthaginian second line. As the Hastati pursued them (at a walk), the dead and discarded weapons lying about caused the Hastati battle line to break up. When the Principes followed up the Hastati, their battle line also started to break up due the dead and debris. It was at this moment the officers of the Principes wisely ordered them to stand firm. The Principes took up position with the dead and the debris in front of them as confirmed by Polybius:

Then he (Scipio) regrouped the Hastati in the forefront of the ground where the battle had just been fought, and…ordered the Principes and Triarii to deploy and, picking their way over the dead...

The action by the officers of the Principes portrays the trust Scipio had in his lower echelon commanders. These officers were in a good position to make such a judgment and appear to have the command authority to do so. The actions of Laelius and Masinissa by immediately attacking and capitalizing on the Carthaginian cavalry being thrown into confusion by the rout of the elephants indicates Scipio had given tactical freedom to his subordinate commanders without their need to seek his approval.

Meanwhile the Hastati alone continued to push back the Carthaginian second line and the remnants of the first, creating a growing gap between the Hastati and Principes. Hannibal could not commit his veterans to double envelope only the Hastati and then in response have his outflanking veterans attacked by the Principes. The plan had failed. It is possible, but an argument based only on probability, that Hannibal, adapting to the changing situation, knew if his veterans remained in a two line deep formation and engaged the Hastati, Scipio with his Principes and Triarii would outflank him in a maneuver similar to the one Scipio had successfully conducted against Hasdrubal at the battle of the Great Plains. To prevent this, Hannibal elected to extend his frontage. With an extended frontage Hannibal could still hope, if he was fast enough, to outflank the Roman army. To extend Hannibal’s frontage, the two units of the second line would take up position on either flank of the first line of veterans (now the centre of the line). This maneuver is explained in Aelian’s Manual of Hellenistic Military Tactics:

31.2 It is prostaxis (adjoining) when on each wing of the formation or on one wing alone we add troops to extend the front of the formation.

At this point Hannibal ordered his veterans to force the survivors of the first and second lines to flee out onto the wings of his army and into the open plain. Polybius gives no reason for Hannibal’s decision but it is highly plausible that as Hannibal extended his frontage, this sight must have created further terror for the fleeing second line. Believing they could flee past the flanks of the veterans in their previous frontage, they were now confronted with the problem of an expanding barrier to their safety. Running to the flanks with the Hastati in pursuit was now highly dangerous. Instead of being caught between the anvil and the hammer, terror drove the survivors to try and burst through the veteran line. Such an action would throw the veterans into disorder while they were extending the formation. This would explain why Hannibal, wanting to prevent the veterans from being disordered, ordered his men to lower their weapons thereby forcing the survivors out onto the wings of his army and into the open plain.

During the battle Polybius tells us Scipio removed his wounded, recalled and regrouped the Hastati, and then brought up the Principes and Triarii to take position on either side of the Hastati (extending his frontage). Unfortunately Polybius does not explain the reason for Scipio’s recall of the Hastati, and his redeployment from their traditional three line formation into a single battle line. This is a critical omission by Polybius.

It is possible that Scipio, on observing the routing Carthaginian survivors fleeing further and further out from Hannibal’s centre towards the wings (that would appear to be lengthening in size) realized what was afoot and reacted accordingly by recalling the Hastati, then immediately redeployed his army to match Hannibal’s frontage. We are not informed how long this took but both commanders need the time; Hannibal to get rid of the fleeing troops from disrupting his veteran battle line and Scipio to redeploy his army. No side was in a position to attack the other. From Polybius’ account it seems both lines reformed in time and no tactical advantage was gained by either side. When both lines were set, they advanced. Polybius makes the poignant remark:

The two main bodies hurled themselves upon one another with the greatest ardour and fury. Since they were equally matched not only in numbers but also in courage, in warlike spirit and in weapons, the issue hung for a long while in the balance.

From Polybius’ reference of 12,000 mercenaries in the first line; historians have made the assumption that each line of Hannibal’s infantry was of equal strength (12,000 per line for a total of 36,000) yet there is no evidence to support this. Polybius disputes this by stating when Hannibal’s veteran third line faced the Roman heavy infantry “they were equally matched not only in numbers but in courage.” To explain away the discrepancy of being “equally matched in numbers” historians have proposed that Hannibal’s first and second lines rallied and reformed on each wing of the veteran third line. How these routing troops suddenly become the equal of the Romans in courage is highly questionable. They were not the equal of the Romans before the battle commenced yet seem to improve as a result of being defeated. It is most likely that the mercenaries and Carthaginian infantry were total write offs and continued to flee and take refuge in the Carthaginian camp. For the Roman infantry and Hannibal’s veterans to be equal in number indicates both forces could be in the vicinity of up to 20,000 men.

Another key piece of information to suggest Hannibal’s third line consisted only of his veterans is in the decision Scipio made about deploying the Hastati. According to Polybius, Scipio deployed the Hastati to face Hannibal’s centre. If the modern theory is correct that the first and second Carthaginian lines rallied and reformed on each wing of Hannibal’s veterans (the centre), then Scipio had made a tactical blunder by allowing the Hastati, who, up to this stage, had done all the fighting, to now face Hannibal’s well rested veterans. It would have been more tactically sound to have the Principes oppose Hannibal’s veterans, then redeploy the Hastati to face the rallied Carthaginian first or second lines, thereby allowing tired troops to face tired troops. If the Romans were only facing Hannibal’s veterans then it did not matter where the Hastati were deployed as they would be facing fresh veterans no matter what position they occupied in the battle line. The evidence clearly indicates Hannibal’s third line consisted solely of his veterans.

The outcome of the battle was decided with the eventual return of Scipio’s cavalry. While sustaining attacks from the front and rear, Hannibal’s veterans were defeated.


Throughout Hannibal’s military career, Hannibal’s battle plans showed a distinct characteristic for risk-taking and daring by luring the enemy towards him. At the battle of the Trebbia he purposely lured the Romans to advance and deploy in a position favorable to Mago’s ambush. At the Trasimene, he provoked the Romans into an ambush. Again at Cannae, he projected his centre forward then allowed the Romans to push his centre in and bring them nearer to his Africans. And finally at Zama, Hannibal, still in character, had his second line fall back, bringing the Romans to him.

If there was no censorship of Polybius’ account by the Scipios, then Polybius’ single shortcoming in his narrative, was his acceptance of the facts at face value and his failure to grasp the motivation behind the facts, and because of this, Hannibal’s tactical genius remained hidden from view.


I would like to express my deepest gratitude to Duncan Head and Michael Akinde, who provided valuable assistance, suggestions, and criticisms, both stylistic and substantive, throughout this project. I would also like to thank Jim Webster, and Leon Wu, for their contribution. All interpretations and errors are my own.

This article first published in Slingshot, June 2005.


  1. For Polybius, "The Histories", translated by W. R. Patton (Loeb Edition) and The Rise of The Roman Empire, translated by Ian Scott-Kilvert (Penguin Edition) were consulted. Although both differ slightly in translation the structure and meaning remain the same.
  2. Aemilius Paullus, Quintus Fabius Maximus Aemilianus and Publius Cornelius Scipio Aemilanus Africanus
  3. Appian: Punic Wars
  4. Livy: The War with Hannibal
  5. The Ancient World Volume 19. Nos. 1 & 2, 1989, translated by Professor A. M. Devine
  6. Maurice’s Strategikon: Handbook of Byzantine Military Strategy, translated by George Dennis.

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