Cannae sat at the bottom edge of an immense treeless plain, the largest south of the Po. It was ideal for cavalry operations and large-scale maneuvers, exactly the terrain for magnifying Punic military advantages. By this time Hannibal probably understood that the Romans were intent on a showdown and were putting together a monster of an army for the occasion. So far, his efforts to chip away at the Italian alliance had come to nothing. He needed a really spectacular victory to generate the kind of political impact to begin breaking off Rome’s affiliates. This was the perfect time and place to inflict it. Staying here was tantamount to accepting the challenge. He had only to await his opponent’s arrival.

But, being Hannibal, he probably kept himself busy preparing the reception. If we accept Polybius’s version of the events leading up to the battle, the Punic army may have been alone at Cannae for several weeks. This is a dangerously long time to give any commander to prepare a battlefield, much less a commander with Hannibal’s fertile military imagination. By this time he was likely on a first name basis with every rise and depression, every twist in the River Aufidus, every potential campsite, every approach and escape route, every possible advantage he could squeeze out of the surroundings and then blend with a battle plan that seems to have been derived from his cumulative observations of Roman fighting tendencies and the capabilities of his own troops. As always, much remained to be determined by chance and the circumstances of the actual engagement, but it’s a safe bet that during this respite Hannibal’s mind seldom wandered from the upcoming test.

His plan when it was finally hatched implied a great deal of faith in his army. This faith was not misplaced. The gang of desperadoes that had stumbled off the Alps not much more than a year and a half earlier had been but a scrawny prototype of the force that now awaited the Romans at Cannae. Freeze-dried no more, the men and horses had regained their health, had eaten their fill, and were rested. We know that key elements had been systematically rearmed with the best of the captured equipment, and it is likely that many others had picked up bits and pieces of what had once been Roman weaponry.

Another change had to do with the Gauls. By this time they were much more reliably integrated into the fighting force. They still fought together, to take advantage of their peculiar tactical characteristics, but at Cannae small units of Gauls were interspersed with Spaniards, indicating that their tribal allegiances had been effectively superseded by the command system that controlled the rest of the army. Very likely the process that had begun for the Gauls on the slog through the Arno marshes was now complete. They were now not only fierce and brave individually; they were also disciplined, well trained, and above all reliable at the unit level. And as such they would play a critical role at Cannae.

Psychologically, this was an army that had known nothing but the most decisive sort of success since it had entered Italy. In a life-and-death struggle, confidence is crucial, and the recent past had given these men every reason to believe in their own fighting skills, as well as their commander’s ability to drive opponents into positions of utter vulnerability and near helplessness. Many must have already killed Roman soldiers personally and must have also observed them reduced to an abject state, begging for mercy. That was Hannibal’s point when he reassured an officer worried about the size of the opposing force at Cannae. (“In all this multitude there is no one who is called Gisgo.”) For Carthaginians, more Romans simply meant more Romans to kill. This was the dark side of a truly professional fighting force, especially one that fought with edged weapons; they were used to killing, inured to it. They would kill without hesitation. It was a terrible advantage that the Carthaginians had and that most of the Romans at Cannae lacked.

Nowhere was this more evident than in the cavalry, probably the most lethal Punic fighting component. As had been true since Trebia, the Spaniards and Gauls rode together as a shock element, although now they were almost certainly better trained and integrated. The Spaniards carried two light throwing spears, a sword, and a round shield, or caetra. The Gauls, primarily composed of nobles, were more heavily armed and armored, with chain mail, metal helmets, and a stout thrusting spear. The two groups would have been an impressive one-two combination, with an initial hail of javelins followed by closer, more decisive engagement. This was a force more than capable of taking on anything the Romans had on horseback, and likely predisposed to fight in the same very confrontational way—one entirely different in its ethos from the other face of Punic cavalry.

They were the Numidians, Hannibal’s version of killer bees, proverbially swarming their opponent if given even the slightest opening. The Numidians were the closest thing a western Mediterranean battlefield saw to an inner Asian steppe horseman. They lacked only the steppe horseman’s deadly composite bow, relying instead on a brace of light javelins and a slashing dirk. Characteristically, Numidians pinned and herded their foes through absolute mastery of their hyper-agile ponies, and then ran the enemy down with ruthless efficiency, able to cut their hamstrings even at a full gallop. Like the steppe horsemen, they were fatally easy to underestimate. Riding bareback and carrying only a light shield for protection, they avoided hand-to-hand combat and were largely incapable of direct confrontation. Polybius describes them as “easily scattered and retreated, but afterwards wheeled round and attacked with great daring—these being their peculiar tactics.” Yet in the hands of a commander as opportunistic as Maharbal, they could destroy an entire force once it became even slightly demoralized and ready to bolt.

All together, Hannibal’s cavalry now numbered around ten thousand, two thirds more than when he’d entered Italy, and more to the point, they were enjoying a five-to-three quantitative edge over the Cannae-bound Romans, whose horsemen were by far inferior in quality also. Looked at another way, the Carthaginian force had one horseman for every four foot soldiers, while the Roman ratio was one to thirteen, a strong indication that the Punic army was far better adapted to the flat terrain on which the battle almost certainly would be fought. All in all, it constituted a yawning gap, and one that would soon send the Romans stumbling down the initial steps toward tactical ruin.

Hannibal’s close order heavy infantry probably numbered around thirty-two thousand at this point and came in three varieties: Gauls, Iberians, and Libyans. Despite the heavy infantry’s having suffered relatively severe casualties at Trebia and Trasimene, there probably remained around sixteen thousand Gauls, whose shock value and increased reliability we have already considered. There were likely about six thousand Spaniards left at this point, a fraction of the original contingent that had made up the bulk of the army when it had departed New Carthage. In Darwinian terms, we can assume the fittest survived. Nevertheless, Polybius leads us to believe they wore no armor, but only a purple-bordered linen tunic, and possibly not even a helmet; but since a lot of captured Roman equipment was available, this may not be entirely accurate. Tactically, these Iberians were most interesting because they fought like Romans, first throwing a heavy javelin not fundamentally different from a pilum, and then weighing in with either a straight or a curved short sword and a large oval shield. Interspersed with Gallic units, they could be construed as having had a stabilizing effect on the critical center at Cannae, allowing the more impulsive Gauls to rush forward, hack away for a while, and then fall back, leaving the Spaniards to fight the pursuing Romans on their own terms.

Finally, there were the Libyans, presumed to be Hannibal’s best-drilled and most elite maneuver element, since they were the first to receive Roman equipment and because they formed the jaws of the trap that snapped shut on the Romans at Cannae. Thus far he had used them scrupulously and in ways they would take few casualties, so of the twelve thousand who had come down off the Alps, probably around ten thousand remained. But if these African spear-fighters formed the teeth of the Punic force structure, the other elements were the claws and muscle and sinew of this beast of battle. Hannibal’s genius as a commander was his ability to devise and execute a plan that used all the parts in concert to swallow and digest a much larger prey.

The Romans had no trouble locating Hannibal, since he was hardly hiding, and they set up camp initially approximately six miles to the east on the broad plain that runs down to the Adriatic. There ensued an elephantine pas de deux, as the two armies warily closed the distance while at the same time trying to gain some tactical and psychological advantage.

The Romans, however, were literally of two minds, since Varro and Paullus followed the tradition of alternating command daily when consuls operated together. Because of the curtain of blame later cast over Varro, it is hard to separate actual disagreement between the two consuls from aspersions dumped on Varro retrospectively. If it is conceded that both consuls wanted to fight, and most modern historians do concede this, the evidence such as it is points to Paullus as the more cautious of the two, particularly worried about being caught on the flat ground ideal for Carthaginian cavalry.

The vicinity of the anticipated field of battle was dominated by high ground to the southeast, where the abandoned town of Cannae and Hannibal’s first camp were located, and bisected by the River Aufidus, a shallow, narrow watercourse running in a northeasterly direction toward the sea. The terrain to the northwest, over and beyond the left bank of the river, was broad and flat. The area between the right bank and the highlands toward Cannae, while still level, was more broken and constricted. Hannibal almost certainly preferred the left bank but could and would fight on the right side; both Roman consuls wanted to avoid the left side and stage the battle in the most confined area possible. The days preceding August 2, 216, were an extended test of wills that saw Hannibal unsuccessfully harass the Romans with light troops as Varro initially approached. Then Hannibal moved his camp to the left bank and formally offered battle on this side, first to Varro and then to Paullus, only to be refused. Finally, Hannibal sent Numidians after the Romans’ water bearers, and this gesture provoked the Romans into action, albeit on the right side of the Aufidus. Meanwhile, the Romans had moved too close to withdraw safely, and so they split their army into two camps, leaving two thirds on the left side of the river and the remainder in a smaller enclave on the right bank. The stage was set.

The Roman battle plan at Cannae can be summarized in three words: “pack the middle.” Because this approach would play into Hannibal’s own scheme and lead to a great disaster, it is easy to dismiss the plan as nonsensical. It wasn’t. Rather, it had a clear purpose, to maximize the Roman numerical advantage in infantry while minimizing the obvious Carthaginian superiority in cavalry. It was also based on past experience. At Trebia, ten thousand legionaries had finally managed to hack their way through the center of the Punic line, and had they been able to do it sooner, they could have split and pivoted to crush the Carthaginians attacking on each flank. Even amidst the surprise and demoralization of Trasimene the impetus of around six thousand Romans had carried them through the Carthaginian stopper force, only to be captured later. We can assume that Varro and Paullus and those advising them were confident in the ability of their troops to puncture the heart of the Punic line, and were intent on doing this as rapidly as possible. Geometrically this called for a narrow, thick formation, exactly the configuration on the day of the battle described by Polybius, “placing the maniples closer together than was formerly the usage and making the depth of each many times exceed its front.”

Breaking though in this manner was decidedly not a matter of simple momentum, like some gigantic rugby scrum pushing inexorably forward. Romans fought primarily with short swords, so the cutting edge was by definition the first line of combatants. True, pila could be launched from several rows back, but any soldier behind around line eight would probably have hit a fellow Roman up front.

The real arguments for this type of human geometry had to do with order, endurance, and psychology. Long narrow columns are easier to keep together, and, they therefore move faster and more cohesively on the battlefield. The many lines to the rear also insured an almost inexhaustible supply of fresh fighters to take the place of the fallen and exhausted, a kind of conveyor belt of shark’s teeth. Finally, a great many of the Roman participants at Cannae lacked combat experience; the middle of such a formation was a safe, psychologically reassuring place for them. One source equates this to the human instinct to herd together for mutual comfort, but without considering that this was actually prey behavior. The thickened manipular order could be expected to have massive combat endurance, which would make the formation almost impossible to defeat by frontal attack, and would thereby allow the unit to move steadily forward. But what would happen if it faced the unexpected, was hit from an unanticipated direction? At this point herding behavior might become just that, dissolving the maniples into a crowd compressed to the point of mass helplessness. The legions would lose the ability to replace frontline fighters through now nonexistent gaps between units. It was a prospect not pleasant to contemplate, and one we can be pretty sure the Romans failed to consider.

Hannibal may have. Just how much he knew of the Romans’ plans prior to battle is impossible to say. Though Livy maintains that “all the circumstances of his enemies were as familiar to him as his own,” whether Hannibal understood beforehand the degree to which the Romans would pack the middle remains open to question. Yet his experience fighting them would have warned him of their will and of their ability to break through in the center, and the likelihood of their trying it again. Also, given his knowledge of Greek military practice, he was doubtless familiar with the Athenian tactics at Marathon in 490, when the Greeks withheld their center and crushed the Persians with their wings. As the day of battle approached, all of this must have been taking root in Hannibal’s fertile brain as he roughed out the framework of an even more lethal trap. As we shall see, the final details would await the contingencies of the battlefield, but the basic plan of using the Romans’ own greatest strength against them was inherent in Hannibal’s deployments and therefore had to have been plotted in advance.

Though there is a tradition of viewing Hannibal as simply being up to his usual tricks—hidden attackers and fake surrenders—the key deception at Cannae was far more subtle. In essence, the trap was hidden in plain sight, something that even today does not seem to be fully understood. Basically he planned to string a line of combined Gauls and Spaniards between two very deep columns of Libyans positioned on either flank, so that viewed from above the formation would look like a backward block letter C. The idea was that as the legionaries rushed forward, the Gauls and Spaniards would give way in a measured fashion (this was critical), leading the Romans farther and farther in between the two columns of Libyans, who would then be in a position to stage a devastating simultaneous attack inward from either flank, stopping the Romans dead in their tracks and leaving them all but surrounded.

Maps of the battle, which are invariably drawn from a bird’s-eye perspective, make the net results clear enough, but also reveal the central deception in a way that leaves open the question: “Why would anyone be dumb enough to walk into such an obvious trap?” But from ground level it would have been far from obvious.

The analogy of American football is helpful. This very intricate game can be enjoyed and understood by the public precisely because it is viewed from on high; the deception is designed to be seen at ground level, and from this perspective deceptions are profoundly confusing, requiring all manner of coaching, cues, and experience so that players are not fooled on every play. As the Romans approached the Carthaginian line, all they would have seen was a continuous line of men, with no way of knowing the varying depth at either side. As the Romans pushed forward, their attention would have been focused straight ahead and toward the center, where they were making the greatest progress. When the Punic flanks attacked, most of the Romans would not have realized it was even happening. They would have known only that their body of men had strangely come to a halt. By this time it would have been too late. They were as good as dead.

Assuming that Hannibal did not have direct knowledge of the Romans’ plans and simply had to anticipate what they might do, the Carthaginian’s plan faced several worrisome contingencies. Expecting his adversaries to pack the middle implied they would deploy on a fairly narrow front, not much wider than his own. Should the Romans march onto the battlefield in a more normal formation, their advantage in numbers would leave the Carthaginian line seriously outflanked on both sides, affording a perspective that would not only betray the depth of the Libyan columns, but also would force the Carthaginians to abandon the ambuscade by pivoting outward to make up the difference. Also, the Roman and allied cavalry could not be ceded the initiative; if they were allowed to sweep around to either side of the Carthaginians, the jaws of the trap would be revealed and their commanders could be warned before it was too late. None of this happened; instead the Romans played into Hannibal’s hands as if choreographed.

As the sun rose on Tuesday, the second day in August, the scarlet tunic signifying battle could be seen displayed above the tent of Terentius Varro, whose turn it was to command the Cannae army. Polybius says Varro’s men were eager for the fight, were at a near fever pitch of anticipation from the waiting. Orders would have been distributed to the tribunes in the night. The tribunes then would have assembled the men and cavalry in time to march out of camp just after dawn, cross the river, and join the troops in the smaller encampment on the right bank. All were now present, with the exception of ten thousand (probably a legion and an ala) left to guard the main camp and stage an assault on the Punic encampment during the battle. It is likely that the men guarding the main camp were the bulk of those fated to survive the day and become the living ghosts of Cannae. Those less fortunate, around seventy-six thousand men, would move into the customary formation—velites out front; triplex acies, compacted in the middle; and cavalry on the flanks—all awaiting the Carthaginians and destiny.

But exactly where were they? The short answer is that we will never know the precise site of the battle for sure; but that said, the issue has stirred up enough controversy over the years to make it worth considering. Geographically, there are basically two reference points—the location of Cannae itself and the River Aufidus, now called Ofanto. There are also two reliable historical artifacts: we know from Polybius that the battle was fought on the same side of the river as the smaller Roman camp, and the Roman line faced roughly south, with its right flank anchored by the river. It also makes sense that the Romans would have wanted their left flank resting against the highlands on which Cannae was perched, the idea being to make it impossible for Hannibal’s cavalry to sweep around either side to envelop them. The problem is that the distance between the bluffs and the modern Ofanto is far too narrow to accommodate anything like the size of the Roman army, no matter how compacted.

This led a number of respected scholars to propose that the battle was actually fought on the left side of the river, or on a broad plain to the east of Cannae. But the problem with the first view is that it clearly contradicts Polybius, who seldom made this sort of mistake; the drawback to the second is that the flat area to the east is easily wide enough to give Hannibal’s cavalry complete freedom, which raises the question of why Varro would have bothered crossing the river to fight there. Yet all of these interpretations assume that the course of today’s Ofanto is identical to that of the Aufidus, likely a bad bet, given the passage of twenty-two hundred years. This assumption is questioned by modern historians Peter Connolly and Adrian Goldsworthy. Their ingenious alternative is that the ancient river ran considerably to the north as it passed Cannae, leaving flats of about 1.3 miles, wide enough to fit the Roman order of battle as it was assembled that day. This hypothesis remains open to conjecture, but this alternative location seems to be the most plausible for what would shortly become the most prolific killing ground in the history of Western warfare.

If this was indeed the point of deployment for the Romans, it must have inspired great confidence. The inexperienced citizen and allied cavalry, stationed at the extreme ends of the line, right and left respectively, had been relieved of any offensive responsibilities; the cavalry had simply to guard the flanks while the infantry did its work.

Similarly, the numerous but qualitatively inferior velites that were spread out in front of the army had no particular mission once the force was deployed, and they could conveniently retreat between the maniples if pressed.

Meanwhile, the reinforced triplex acies seemed unstoppable, and if anything slowed it down, it was at least impenetrable. It must have appeared to Varro and Paullus that they had finally positioned their forces in a way that even Hannibal could not bend to his own advantage.

Now it was his turn to do just that. Hannibal apparently sent the Balearic slingers and Numidian foot soldiers across the river at about the same time the Romans crossed, but the mission does not seem to have been to interfere with enemy deployments so much as to set up a perimeter behind which the Punic cavalry and heavy infantry could line up. When this was done and he was certain the Romans were ready to fight, Hannibal followed. We can conjecture that the cavalry crossed the river first to reinforce the screeners. Next the Gallic and Spanish infantry joined them, lining up in the center, followed by the two bodies of Libyans, who took their place on either side but remained in columns to form the backward block letter C. By this time the horsemen would have split apart and moved to the flanks, the Spanish and Gallic heavy cavalry on the left facing their Roman equivalents, and the Numidians on the right matched against the allied mounted elements.

As orderly and purposeful as these pre-battle rituals seem in print, the real thing must have provided, even before the fighting started, plenty of distractions and cause for disorientation. At this point the field must have been a jumble of cacophony—horns blaring, drums pounding, swords beating on shields, shouts and war cries reverberating back and forth, to and fro—all the sounds that men muster as they steel themselves to face death and intimidate those they hope will be their victims. Also, more than 125,000 men and in excess of 15,000 horses tramping about in a confined area must have kicked up huge quantities of dust, and it appears that Hannibal’s familiarity with the environment now dovetailed with his desire that the Romans not accurately perceive the true nature of his infantry formation. He had apparently observed earlier that a southeasterly wind, the Vulturnus, gusted with increasing force during the morning, and could be counted on to whip up the dust and blow it into the Romans’ faces, a vexation apparently confirmed by a fragment from the near-contemporary poet Ennius.

Finally, and probably most important, this was August in southern Italy; we can count on it having been hot, and it was bound to get hotter as the day progressed. Most of the Roman heavy infantry and at least the rearmed Libyans would be burdened with between fifty and eighty pounds of arms and armor as they fought for their lives throughout the day. If Trebia had been orchestrated by hypothermia, Cannae was destined to be an inferno where untold thousands were likely to be felled by heat exhaustion, and access to drinking water may well have allowed the Carthaginians to persist in their butchery during the last and most murderous phases of battle.

So it was as they began to fight. The ancient sources agree that the light troops were first to engage, and from Polybius we hear they were evenly matched, neither side gaining an advantage before withdrawing, as was customary, behind their respective lines of heavy infantry. It seems the velites’ numerical preponderance had won the Romans at least a standoff—an auspicious start, considering the multiple drubbings they had taken on earlier occasions.

The first decisive Punic move came when the Spanish and Gallic cavalry under Hasdrubal—leader of the service corps and destined to perform brilliantly on this day—charged headlong into the opposing horse on the Romans’ right flank. With their adversaries anchored on the river and outnumbering the Romans by more than two to one, there were none of the normal wheeling maneuvers. Instead the Carthaginians seemed intent on going right through the Romans.

The combat that ensued, Polybius tells us, “was truly barbaric.” In large part this was because it was mostly on foot. Roman cavalrymen had a decided proclivity toward fighting on the ground, and many of these troopers must have been inexperienced and new to their mounts—a development that supposedly caused Hannibal to comment: “This is more to my wish than if they had been handed over to me in fetters.” While it is unlikely the Punic commander actually observed the cavalry getting off their horses, the act nonetheless proved fatal to most of the outnumbered Romans, who were basically annihilated. This is also where many of the Roman senators and others of the equestrian class would have gathered to fight, and ended up making their last stand. And it would only get worse. Rather than chase down the last of the survivors who managed to get back on their horses and flee, Hasdrubal reeled in his men from the pursuit, then rested and re-formed them to inflict further mayhem on another part of the battlefield.

Meanwhile, the heavy infantry engagement had begun and had already taken shape, literally, in an unexpected way. As the line of Gallic and Spanish infantry advanced (one source estimates the formation was roughly 840 men wide and 26 deep), it bowed outward to form a crescent. While some maintain this was natural for a line of men moving forward, others believe it was a last-minute decision on Hannibal’s part. Whichever it was, this convex formation had an immediate and beneficial effect for the Carthaginian side. For as the Roman hastati charged and reached pila-throwing distance, the shape of the line left only a narrow group in the Punic center vulnerable to this potentially devastating missile barrage, and may have led many legionaries to waste their shots while still out of range.

The same thing would have happened as the sides closed for sword-play. Initially at least, the Roman manipular order and their own training would have more or less automatically kept their line straight, and so only the center group of Spaniards and Gauls would have been engaged. The key to Punic success turned on the interior line retreating slowly and in a controlled manner. This was why Hannibal and his brother Mago (presumably joined by other officers and Celtic nobles) stationed themselves here, immediately behind the front, to better manage the action and encourage these most critical of fighters. And the initial geometry of battle served exactly its purpose by committing only a relatively few combatants, and by keeping the huge Roman force at bay until the legionaries in the middle managed to push those at the Carthaginian center back.

As we imagine clusters of bare-chested Gauls flailing their broadswords, interspersed with Spaniards fighting from a crouch behind their shields, all seeking to fend off the surging Romans—themselves bashing forward with their scuta, seeking an opening for their gladii—we should not forget that this sort of combat, essentially a series of individual duels, was both physically and emotionally exhausting. It could not be sustained for more than a few minutes. Once the Punic line failed to collapse immediately, these spasms of violence had to be followed by rest periods when both sides drew back to catch their collective breath for a few minutes. War cries and insults might have been hurled back and forth, followed by pila and other projectiles picked up or passed forward, and then close combat would have been reinitiated. Over time the lulls would have grown longer and the mêlées shorter.

This interrupted rhythm of violence also was to the Carthaginians’ advantage, allowing them to regroup, regenerate, and fall steadily backward in relatively good order. Seeing this, the Romans naturally pushed ahead with increased confidence and growing excitement, focused on their objective of breaking through at the center as quickly as possible. As this happened, the retreating Punic line began to assume an increasingly concave shape, and a critical juncture was reached. Polybius reports that the Gallic and Spanish infantry in the middle were forced into such a rapid retreat that the Punic line started to break up. As the Roman tide surged forward, it cast caution and training aside and followed the line of least resistance, crowding inward toward the center. The intervals separating the three lines of the triplex acies, and the spacing between maniples, disappeared, and its general organization started to disintegrate. Collectively, the legionaries thought they could see victory just ahead, but it was a mirage; instead, as-yet-unnoticed defeat stared them down from either side in the form of two serried blocks of Libyan heavy infantry, the jaws to the Carthaginian trap.

The moment of Hannibal’s killer epiphany had arrived. The order went out, and man by man the Africans on both the left and right sides pivoted inward, dressed their ranks, and in unison fell upon the Roman flanks, most likely the location of the least-experienced citizen and allied troops. There was little the Romans could do in response besides turning as individuals to face the threat; as units, their formations were too compressed and disorganized to maneuver effectively. They were reduced to a crowd of loners trying to fight off a coordinated engine of destruction. Meanwhile, the emotional shock waves rippled inward, spreading paralysis throughout the Roman ranks and halting the forward momentum of the entire army. Their fate was all but sealed.

Hasdrubal, fresh from obliterating the Roman horse on the other side of the combat zone, led his reconstituted force of Gallic and Spanish heavy cavalry across the battlefield behind the deployed lines of legionaries, and was soon bearing down on the allied horse with a force that was nearly twice the size. But even before the Carthaginians could bring the charge home, their intended victims evaporated in a panicked stampede, apparently sweeping Varro and his attendants along in their wake. The Numidians, devastating in pursuit, took off after them, killing or capturing all but three hundred of the allies.

The focus of Hasdrubal's appetite for destruction remained unerring. Rather than rising to the bait of the chase, yet again the Punic commander re-formed his cavalry and instead headed toward the rear of the Roman infantry, quite apparently intent on closing their last avenue of escape. Here, Polybius tells us, Hasdrubal delivered multiple charges at different points, seemingly with devastating effect. On first glance this seems puzzling, since the triarii in the rear should have been well equipped to turn and resist, lining up on one knee with their shields resting against their shoulders and their long spears protruding to form a barrier that horses would not charge. But instead of a solid wall of triarii, it is far more likely the Roman rear was cluttered with a soft mass of up to twenty thousand velites, who had withdrawn behind the maniples shortly after the battle had begun. Most of them were probably adolescents, were very lightly protected, and were lacking room to throw their javelins, and with no avenue of escape, they were virtually the perfect prey for heavy cavalry. Terrified by the horses and the slaughter of their comrades, they would have recoiled inward, exposing their backs and hamstrings to spear thrusts and sword slashes while they pressed desperately against an ever more compacted and undifferentiated human mass.

The same crowding into helplessness must have been taking place on the flanks, as the Libyans on either side continued to press home their attack, an ever-tightening human vise. Meanwhile, the nearly routed Gauls and Spaniards, no longer pursued by the Romans at the forward edge of battle, would have been given time to regroup and turn the tide in their favor. A terrible dynamic was taking place. Assailed from all sides, beyond the control of its officers, with those on the outer edges having no place to go but inward, the Roman army, by pressing itself into paralysis, was becoming if not the instrument of its own destruction then at least complicit in the process.

Somewhere between sixty-five thousand and seventy thousand Romans and allies—depending upon how many had already fallen—were now surrounded. Tactically the battle was over, but the killing had just begun. There was no alternative. The army was still too large and full of fight to be taken prisoner; besides, with its leadership immobilized in the press, it had no real means of surrender. The only choice was its effective extermination, a task the Carthaginians accomplished through systematic butchery almost until the sun set on this terrible day.

Not only does the process beggar description, but exploring the details of the massacre might seem to serve little purpose beyond pandering to some bloodlust with a kind of pornography of violence. Yet war is truly terrible, and to turn our eyes away from its results is in itself an act of cowardice. Hannibal’s great victory, his tactical masterpiece celebrated through the ages, produced, in the end, little more than corpses. But this is probably better illustrated by recounting the subsequent course of events than by moralizing over it now. Nevertheless, there is a more prosaic but still historically valid reason for prying into the details of this exercise in mass homicide. As one source put it, “What remains unclear is how encircled troops, with nowhere to run, could be slaughtered in such a one-sided fashion.” We live in an age when killing is cheap, virtually automated; that was far from the case at Cannae. Other than those who succumbed to the heat, each of the men who died had to be individually punctured, slashed, or battered into oblivion. One modern source estimates that in order for the necessary killing to be accomplished in the eight hours that Appian estimated the fighting lasted, over one hundred men had to be dispatched every minute. Yet even this astonishing figure underestimates the swiftness and profusion of the slaughter, since the estimate assumes that the killing took place at a regular rate throughout the day and not in a great spasm toward the end, as actually happened. In essence, so many victims, so little time, and that doesn’t even attempt to reflect on the ruthlessness and horror of it all.

Nevertheless, logic tells us that the liquidation of the Roman army at Cannae, if it is possible to reconstruct at all, must have been a matter of mechanics and motivation. We can start here. Among the ancient sources, only Polybius has left us something approaching a plausible description of what must have been the most horrific several hours in all of Western military history: “The Romans, as long as they could turn and present a face on every side to the enemy, held out, but as the outer ranks continued to fall, and the rest were gradually huddled in and surrounded, they finally were all killed where they stood.” In other words, they were finished off from the outside in, peeled like an onion. This makes sense, at least basically, but there were likely to have been other lethal dynamics at work.

Hannibal’s skirmishers—the Numidian foot soldiers and Balearic slingers—having earlier withdrawn to safety behind his main line, must have been intact and available. It’s hard to imagine that he wouldn’t have had them let loose a hail of javelins, stones, and even expended pila onto the stationary mass, a deadly barrage that could hardly have missed in such a target-rich environment, nor avoid inflicting serious injury on Romans who were either too crowded or too exhausted to raise their heavy shields for protection.

Meanwhile, the infantry of Libyans, Gauls, and Spaniards would have continued with their grim work at the circumference. One modern source in an otherwise believable reconstruction of the carnage describes victims “dispatched with frenzied blows, usually to the head.” This seems to miss the mindset implied in the quantity and rapidity of the butchery. Hannibal’s soldiers were practiced killers; very likely most had adopted the cooler, utilitarian approach of the predator, having drawn on our emotional heritage as hunters of the most prodigious and ruthless sort. Moreover, they would have known how to kill quickly and efficiently. If the victim’s back were turned, then a spear or sword thrust to the kidneys would have been so painful as to instantly paralyze, and would have killed within seconds through massive internal bleeding. Or if the victim were facing forward, an equivalent stab to the lower abdomen would have produced the same results almost as fast. Yet such a death stroke—or even more so, multiple death strokes rapidly delivered—implies a certain acceptance, or at least passivity, on the part of the recipient.

This is something the ancient sources—all of them Romans or Roman sympathizers—deny. They would have posterity believe Cannae was, in the words of Polybius, “a battle in which both the victors and vanquished displayed conspicuous bravery,” a battle in which the Romans fought stubbornly to the bitter end. Given what has been learned through modern combat studies, this does not seem likely. Even among elite units, when sufficient casualties have been suffered, the whole group slides into a state of apathy and depression more extreme than is encountered in almost any other kind of human experience. “Unable to flee and unable to overcome the dangers through a brief burst of fighting, posturing, or submission,” writes military psychologist Lieutenant Colonel Dave Grossman, “the bodies of modern soldiers quickly exhaust their capacity to energize and they slide into a state of profound physical and emotional exhaustion of such a magnitude and dimension that it appears to be almost impossible to communicate it to those who have not experienced it.” Were Romans tougher and more stoic than modern combatants? Perhaps, but as far as we know, the mental makeup of the ancients was similar to our own. How else would so many of their recorded deeds make sense to us? It seems, then, that the reason why it was possible to kill so many so fast is that most of the victims faced death without resistance. Would this paralyzing combat fatigue have afflicted everyone, and to the same degree? Probably not. Anecdotal evidence indicates that some would have gone down fighting no matter what the circumstances. But the circumstances were really bad, well beyond the limits of most.

If it is possible to conceive of hell on earth, this human abattoir at Cannae must have been the equal of any hell that history in all its perversity has managed to concoct. Thousands upon thousands packed together, unable to move, beset by the cries of those in extremis, many of them dressed in now useless chain suits and cooking-pot helmets beneath the broiling sun, without prospect of water, only death offering any relief whatsoever. As time passed, more and more men would have fainted from the heat, slid to the ground, and been trampled beneath the feet of their comrades, their bodies and discarded shields tripping still others who would then have fallen similarly to their deaths. At the outer edges especially, but also in the interior, where javelins rained, the ground would have grown slick with Roman blood, which would have brought down still others. As at Lake Trasimene the hopeless would have begged their fellows to finish them—presuming there was room for even a short sword thrust—or simply would have done the deed themselves. The stink of death and all the bodily functions that accompany it must have come to pervade the atmosphere and compound the wretchedness of those condemned to take their last breaths there. There was no place worse.

Here and there it is possible to catch a glimpse, even if it’s only a statistic, of a shadow of an actual person caught in the grip of this misery. We know that of the forty-eight military tribunes at Cannae, twenty-nine did not survive. Most would have died in this central killing field, since it was their job to lead the legions. Both quaestors, Lucius Atilius and L. Furius Bibaculus, were likely here also, as were Geminus and Minucius—all of them dead. If Paullus had not been killed earlier on the wing, as Livy suggests, then he too met his end here—according to Polybius, “in the thick of the fight.” This brings to mind the fate of Paullus’s son-in-law.

Nineteen-year-old Publius Cornelius Scipio was young for a military tribune, but he had already seen a lot. He had saved his father’s life at Ticinus and had likely been part of the disaster at Trebia, and perhaps even at Trasimene. At Cannae we know he was attached to the Second Legion, and, given his social standing and his relationship to Paullus, it doesn’t seem likely that the young Scipio was with the ten thousand left to guard the camp. So probably he found himself caught in the dwindling remains of the Roman infantry, once again ensnared by Hannibal’s trickery. It must have been a learning experience, but perhaps a futile one in the face of almost certain death. Yet, contrary to all expectations, he would survive and elude capture, as did thousands of others also apparently hopelessly trapped. Here again this seems to have been a matter of mechanics.

Body buildup had to have become the central problem of the Carthaginian executioners, piles of dead obstructing them from getting at more Romans, not to mention all that slippery blood. A point of diminishing returns must have been reached and a new approach required. Logically this would have suggested a change of venue, a shift in the killing field to less cluttered terrain. The controlled release of clumps of legionaries away from the main mass would have effectively served this end. These Romans could then be run down and killed (or taken prisoner). But this also would have opened a window of opportunity for the Romans, who might have organized into wedges capable of defending themselves until they could reach either of the two camps and some sanctuary, however temporary. Many never could have made it, especially if they got separated. But chance, this opening, and the inevitably growing exhaustion of their Carthaginian tormentors would have collaborated to sweep away from this disaster the core of a class of survivors who would live to fight another day. Young Scipio, it seems, was one of them.

Finally the killing must have trailed off. Polybius maintains that Hannibal rounded up approximately two thousand Romans who had climbed up and hid in the ruins of Cannae, and also captured both Roman camps immediately after the battle. While Hannibal may have captured the refugees in the ruins, it doesn’t seem likely that his troops were in any shape to overwhelm a fortified area, no matter how dispirited the inmates. Sleep was probably the only item on their agenda.

If this makes sense, then Livy’s story of what went on in the two Roman camps that night appears believable. Most of the men seem to have been in shock. But those in the larger enclave, having avoided the main disaster and having participated in only a brief failed attempt on Hannibal’s camp, were probably in better shape. These men were still organized and were being led by their officers, who undoubtedly were aware that their present position was untenable. They sent a runner to the smaller camp and ordered them to break out and join forces, so that both elements could slip away under the cover of darkness and make for Canusium, a walled town about twenty-five miles to the southwest. The message fell on deaf ears, until one of the surviving military tribunes, P. Sempronius Tuditanus, made an impassioned speech and got six hundred (Frontinus says it was only sixty-two) men to follow him out to join the others. Not everybody from the big camp was willing to leave. But Livy indicates that some four thousand legionaries and two hundred cavalry in this group arrived safely at Canusium, where they were eventually joined by several thousand other survivors; meanwhile, another forty-five hundred found their way to Venusia, where Varro had taken refuge. All of these men were destined to be reorganized and branded with the stigmatic title legiones Cannenses, the living ghosts of this terrible battle.

How terrible? Dawn of the next day revealed approximately 45,500 legionaries and twenty-seven hundred cavalrymen strewn about a space not much larger than a single square mile. As the Carthaginians set about despoiling the bodies and searching for their own among the dead and half dead, even they were shocked by their handiwork. Livy, the ancient cinematographer, leaves us a scene as surreal as any other in military history:

Here and there amidst the slain there started up a gory figure whose wounds had begun to throb with the chill of dawn, and was cut down by his enemies; some were discovered lying there alive, with thighs and tendons slashed, baring their necks and throats and bidding their conquerors drain the remnant of their blood. Others were found with their heads buried in holes dug in the ground. They had apparently made these pits for themselves, and heaping the dirt over their faces shut off their breath. But what most drew the attention of all beholders was a Numidian who was dragged out alive from under a dead Roman, but with a mutilated nose and ears; for the Roman, unable to hold a weapon in his hands, had expired in a frenzy of rage, while rending the other with his teeth.

If this does not give pause, it is possible to resort to statistics. By way of approximation we can consider each Roman weighed 130 pounds—they were lighter than modern men. Then there would have been well in excess of six million pounds of human meat left to rot in the August sun—the true fruits of Hannibal’s tactical masterpiece, at least for an air force of vultures.

The fate of the others remaining at Cannae was not much better, particularly if they were Roman citizens. According to Livy’s timetable, Hannibal, after allowing his troops much of the day for looting, next made short work of the two camps, gathering up nearly thirteen thousand prisoners. When these men were added to those taken from the ruins on the hill and to those taken from the battlefield, the total was slightly more than nineteen thousand captives. Many of the Romans would end up as slaves in Greece and Crete, still there more than two decades later—another of Cannae’s many legacies.

Hannibal too was left to wrestle with the outcome of Cannae. The fight had cost him between fifty-five hundred and eight thousand men, but at least half of these had probably been Celts, and the army was basically intact. Meanwhile, his men had recovered gold rings numbering in the hundreds, some taken from captives but most pried from the lifeless fingers of senators and equestrians. In a single day Hannibal had decimated a substantial proportion of Rome’s leadership, a blow that some might well have considered mortal. Maharbal, Hannibal’s brilliantly opportunistic cavalry commander, was apparently one who thought so. Livy tells us that sometime after the battle, amidst the congratulations of the Barcid’s henchmen, Maharbal warned that no time was to be lost, and held out instead the prospect of dining in the enemy capital within five days. “Follow me: I will go first with the cavalry, that the Romans may know that you are there, before they know you are coming!” It was the most audacious of proposals. March on Rome! Finish it now! When Hannibal hedged and refused to make an immediate decision, Maharbal’s reply was equally impulsive: “So the gods haven’t given everything to one man; you know how to win a victory, Hannibal, but you don’t know how to use one.”

Assuming the incident actually took place—it was very much characteristic of both men: Maharbal seizing the main chance, and Hannibal the gambler growing cautious in the face of overwhelming good luck—it strikes at the heart of Punic prospects and is therefore hotly debated. On balance, scholarly opinion seems to support Hannibal for not trying it. Some argue that he was short on pack animals and the logistical support needed to move his army 250 miles to Rome with the necessary alacrity. (This argument seems odd, given the journey from Spain and the Carthaginians’ tromp through the swamp.) Other scholars maintain that even if he had gotten to Rome, he couldn’t have done much productive, and he lacked siege equipment. (He could have built some.) Still others are of the opinion that Hannibal was better off trying to break the Roman alliance, win on a solid base of support, and then negotiate. (We shall see how that worked out.) In fact there were many good reasons for not marching on Rome, and only one good reason for going.

Unlike the scholars, Field Marshal Bernard Montgomery, a soldier, thought Maharbal was right. Maharbal seems to have understood that when a more powerful adversary is down, it has to be dispatched. Rome still had huge manpower reserves; there was no such thing as a peace party; this was a state that bargained only with the defeated. Hannibal’s single chance of winning the larger war was to begin marching his army toward Rome. Even if it had taken him a month to get there, the tension in the city would have only built with reports of his coming. And ultimately his appearance outside the walls might have broken the spirit to resist, or might have led to Rome’s sending an ill-prepared force out to another catastrophic defeat and ultimate capitulation. Or not. In the end it still would have been a long shot. But it was his only shot. Instead, Hannibal chose another route, and the war became only a matter of time.

Back in Rome the city’s population was on the ragged edge of panic, “expecting Hannibal every moment to appear,” Polybius tells us shortly before he effectively signs off, the remainder of his description of the war surviving only in fragments. For better or worse Livy becomes our primary oracle, framing subsequent events with a dramatist’s eye.

Accordingly, Rome’s streets are described as echoing the wailing of lamenting women, because the initial reports indicated that the Cannae army had been crushed and there were no survivors. The senate met to take measure of the situation, with Fabius Maximus arguing for gathering more intelligence, sending the women indoors, and preventing anyone from leaving the city. It was only after a letter arrived from Varro verifying the disaster—but adding that he was with ten thousand survivors at Canusium and that Hannibal was still at Cannae not doing much of anything—that the cloud of terror began to dissipate and enough traction was gained for the senate to begin serious planning. What emerged was a characteristic combination of superstition, practicality, and adamantine stubbornness.

Existentially, beating back the dread and propitiating the gods called for extraordinary—what we would call barbaric—measures. Perhaps conveniently, two of the vestal virgins were found not to be so. One of the two women comitted suicide before she could be buried alive with the other, while the seducer was beaten to death by the pontifex maximus, the chief priest. Meanwhile, the priest’s colleagues were consulting the Sibylline Books for other goddess-calming measures, and found the answer in more live interments—this time two couples, Greek and Celtic, male and female. And if human sacrifice did not prove sufficient, the city fathers thought to send fellow senator and historian Fabius Pictor to Greece to consult the Delphic oracle for more ideas on atonement. In a further attempt to restore emotional equilibrium, the senate officially limited mourning to thirty days, but the senate still had to call off the annual festival to the goddess of the harvest, Ceres, since the rituals required married women who weren’t in mourning, and few were available. Rome did regain its composure, but these steps, plainly meant to be viewed as extreme, reflect the degree to which the news of Cannae had shaken the inhabitants.

Back in Apulia, the Carthaginian was in an avuncular mood. As he had after Trebia and Trasimene, he let the allies he held go free, yet again professing his goodwill. He then turned to the Roman captives and sought to explain himself, which was something new. He was not pursuing a war to the death with Rome, he explained; he was fighting “for honor and empire.” Just as his Carthaginian predecessors had yielded to the success of Roman arms, now it was time for Rome to accept defeat in the face of his own skill and good fortune. It was a speech that might have been given by Pyrrhus or any other Hellenistic monarch, a perfectly reasonable speech. The rules of war as he saw them dictated that, after such a string of beatings, the vanquished, presuming they were in their right minds, admit defeat. That was the way the “great game” of the Mediterranean basin was played; it was time Rome got used to it. He was prepared to be generous. The captives were to be ransomed for a reasonable price; ten of their own number would be sent to Rome to work out the details. Carthalo, a Carthaginian cavalry officer, would accompany them to present Punic peace terms. It’s impossible to know if Hannibal really expected his initiative to work, but it seems unlikely that he anticipated the reception that the delegation actually got.

As the group approached the city, the senate had the dictator, Pera, send a lictor to meet them and inform Carthalo that he would not be received and that he had to leave Roman territory by nightfall. So much for a negotiated peace. There was some sympathy for the captives, but not enough. The captives were not to be ransomed. The senate even went so far as to forbid their families to raise money privately to free them. This plainly went against precedent; just the year before, Fabius had paid prisoners’ ransoms with the proceeds from the farm Hannibal had left untouched. The Roman leadership wanted to send a message not just to its own soldiers, but to Hannibal, to shock him with the degree of their determination. Whatever he might think, in their eyes this was a fight to the finish.

The Cannenses would now get what they deserved, at least in the eyes of the senate. Taxes had been doubled so that all soldiers could be paid in cash immediately, except for those who’d fought at Cannae. They got nothing. But this was secondary compared to being shipped to Sicily. Here they would stay until 204, removed from their families and their livelihood, effectively banished. It was a terrible punishment, inflicted upon them because they were seen as having broken an oath never before required, which had made them, technically at least, deserters. Rome had lost a great battle and needed a scapegoat. Rather than blame the strategists and commanders who had planned it, the powers that be turned on the survivors. The logic, the same as for decimation (“pour encourager les autres”), might have made sense at the time. But these ghosts of Cannae would live to haunt the republic. For one day, legionaries would look to their generals and not Rome for a future, and that perspective would spell civil war and absolute rule. This more than anything else was the battle’s legacy.

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