Background image: The Death of Lucius Aemilius Paullus at the Battle of Cannae, 216 BCE. John Trumbull, 1773. Yale University Art Gallery, 1832.100

Episode 4 in the SHAPS Podcast Series: Professor Nathan Rosenstein

The catastrophic defeat Hannibal inflicted on Rome at Cannae in 216 BCE forced the Republic to drastically change how it would fight the Second Punic War. A strategy of direct military confrontation had to be abandoned in favour of a war of attrition. This strategic shift necessitated a series of additional changes in how Rome mobilised, led, and supported its armies. These changes provided the foundation not only for the Republic’s eventual victory over Hannibal but also for its rapid conquest of the Mediterranean over the following half century.

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Hello and welcome to this episode of Disaster & Change. I’m Kit Morrell, a postdoctoral researcher in the School of Historical and Philosophical Studies, where I specialise in ancient Roman history. This week, in June 2020, I was meant to be running a workshop on the idea and practice of ‘reform’ in the Roman republic. Unfortunately, the workshop was one of countless events around the world that had to be cancelled as a result of COVID-19. Fortunately, Professor Nathan Rosenstein, who was due to give a public lecture as part of the workshop, has kindly offered this podcast as part of the SHAPS Disaster & Change series.

Nathan Rosenstein is Professor Emeritus in the Department of History at Ohio State University. He is a historian of the republican and early imperial periods of ancient Rome, and is particularly known for his work on the relationships between warfare, politics, and socio-economic conditions during the Roman republic. His previous publications include Rome at War: Farms, Families, and Death in the Middle Republic, and Rome and the Mediterranean, 290 to 146 BC. He is currently co-editing a new major work, The Oxford History of the Roman World.

In this podcast, Professor Rosenstein takes us to a turning-point moment in Roman history: the battle of Cannae in 216 BCE, when Rome suffered a massive defeat at the hands of the Carthaginian general, Hannibal. The third century BCE had witnessed the rapid expansion of Roman hegemony across the Italian peninsula. But now Rome’s legions faced an enemy they could not defeat. Hannibal brought to Italy not only tactical brilliance, but what was even more threatening: a credible alternative to Roman power. As Professor Rosenstein shows, Rome’s response was to make radical changes in the way it fought wars and appointed generals — changes that in turn laid the groundwork for the Roman conquest of the Mediterranean world. In this way, looking back at ancient Rome is an opportunity to think about how the decisions we make today, in the face of the COVID-19 crisis, might drive change in the future.

It’s my pleasure to introduce Nathan Rosenstein, ‘Disaster and Change in Republican Rome’.

We are living today through an epidemiological disaster unparalleled in modern memory. What changes the Coronavirus pandemic will bring we cannot at this point know, but history may offer some clues. Still, the ancient Roman Republic might not seem the most promising place to look for them. It certainly never experienced anything like the social disruption and economic upheaval that COVID-19 has caused, but it too had its share of disasters long before the catastrophic civil wars that ended it. The greatest of these without question took place on or about August 2nd, 216 BC at Cannae in southeastern Italy, where Hannibal’s army decisively defeated a much larger force of Romans and Italians. Numbers in the casualty reports of ancient battles are notoriously slippery – some put Rome’s losses as high as 70,000; others at 50. The most careful modern studies set the number lower, around 30,000 killed, captured, or missing. But whatever the true figure, there is no gainsaying the magnitude of the Roman disaster. It was a stunning setback, and coming on the heels of two earlier major defeats it threatened Rome’s hegemony in Italy and the very existence of the Republic itself. Clearly, something had to change in the way the Republic was going to fight this war.

There was never any question that Rome would fight on. Even after the preceding disasters the Republic could still call on tens of thousands of potential recruits. There was no shortage of manpower with which to create new armies. The question was, how to use them.

Over the course of the previous century, Rome’s military strategy had been simple. Its legions and allied forces marched to the enemy’s territory and met its forces in pitched battle where the legions’ tactical superiority generally prevailed. On those few occasions when they lost, Rome simply levied new forces to once again seek a pitched battle. The legions did not win every battle, but they always won the last one. Now however they faced a challenge in Hannibal that that strategy seemed unable to overcome. The Carthaginian’s tactical genius enabled him to beat the Romans in a straightforward fight against overwhelming odds, and nothing indicated that the result was likely to be different no matter how many armies Rome sent against him – at least in the short term. The Republic’s superior numbers might in theory have enabled it to wage a long war of attrition and ultimately weaken Hannibal to the point that it could prevail, but Hannibal had anticipated that possibility and crafted a strategy to counter it.

He knew that half or more of Rome’s military strength rested on the forces it levied every year from its allies – the many cities, towns, and tribes in Italy that Rome had brought under its control as it gradually extended its hegemony across Italy. In many cases, conquest had compelled an ally’s submission, enforced by the threat of Rome’s military might. But they chafed under Roman domination and would revolt given the chance. Elsewhere, locally powerful cities used to dominating their weaker neighbours saw that possibility foreclosed once Rome brought them all under its sway. In numerous cases, too, allied allegiance rested on the loyalty of local aristocrats who controlled their cities’ governments. Personal links between them and Rome’s senators – ties of hospitality, intermarriage, and sometimes kinship – cemented that loyalty and in return for their allegiance, Rome could be counted on to keep its friends in power. Its military might deterred other locally prominent figures who might have hoped to supplant them.

The Republic’s hegemony endured in other words because there was no alternative – until Hannibal. He had arrived in Italy proclaiming that he had come to liberate it. He gave point to that claim in the wake of his crushing victory at Lake Trasimene, the year before Cannae, when he freed all of his allied captives but kept the Romans in chains. Rome’s network of alliances had held firm after that disaster, but in the wake of Cannae it began to crumble. Areas in the Apennine highlands that had long resented their loss of independence rose in revolt and declared for Hannibal. Much more ominously, several important cities, including some that enjoyed a partial Roman citizenship, threw off their allegiance to Rome. Cannae, in their eyes, had demonstrated unequivocally that Hannibal could protect those who joined his side and embraced their freedom.

If they had not before, the senators at Rome now grasped the magnitude of the threat facing them. For as their allies deserted them, Hannibal’s strength grew in proportion as Rome’s declined and added to the forces at his command. The more battles the Republic lost, the more evident Hannibal’s power would become, encouraging more and more defections until Rome stood alone against Hannibal at the head of its former subjects, faced with either surrender or destruction.

To survive, to defeat Hannibal, Roman strategy had to change. The Republic would have to do what it had never done before: avoid pitched battles and fight a war of attrition to wear Hannibal’s forces down to where they could finally be defeated. That would require not only preventing further defections but attacking those allies that had revolted, forcing them to defend their homelands rather than sending their forces to swell Hannibal’s ranks. It also meant preventing reinforcements from reaching Hannibal from Carthage in North Africa or from Spain, his base of operations. And it involved using its forces to harass and impede Hannibal wherever the opportunity arose as he moved around Italy seeking to encourage further defections.

This new strategy also entailed further changes in how Rome waged war. Prior to Cannae, the Republic – with rare exceptions – fielded only two armies each year, each commanded by one of the Republic’s two annually elected chief magistrates – the consuls. Each army comprised two legions of about 4500 men each accompanied by an equal or somewhat larger number of allied soldiers: a total of about 20,000 men. These 40,000 troops constituted only a small fraction of Rome’s total military potential, which was well over half a million Roman and allied men. Now however the Republic was going to have to tap that potential as never before. Starting in the late summer of 216 in the wake of Cannae Rome began to mobilise legion after legion until, by 212, twenty-five were in the field accompanied by loyal allied contingents. Even assuming many of these units were understrength, that figure still represented upwards of 160,000 men. There was only one Hannibal with only one army. Superior numbers enabled Rome’s legions always to be wherever he was not. They could attack defectors, intimidate waverers, and reassure Rome’s remaining friends that the Republic was still a force to be reckoned with. Hannibal could not divide his forces without weakening them and risking defeat where he was not in command.

The senate also kept legions in Spain to pin down Carthaginian forces there and prevent them from marching to Italy to reinforce Hannibal. Others were stationed in Sicily to keep the island loyal and, when Syracuse declared for Carthage, to place that city under siege. After Rome discovered an alliance between Hannibal and King Philip of Macedon, forces were dispatched to stir up trouble and occupy the monarch in Greece. Nor was the war at sea neglected. Fleets prevented supplies from reaching Hannibal by sea and raided North Africa.

Armies need generals, and here, too, Rome had to break with longstanding precedent. Leading Rome’s wars had previously been the privilege of the consuls. Election to that office was always hotly contested because of the honor and opportunities for glory and sometimes wealth that military victory brought to a general. Now, with multiple armies in the field every year, the Republic needed more commanders. Proconsuls filled the gap, former consuls either continued in their commands for one or more years or recalled to active duty to meet a need. Political convention also fell by the wayside as prominent aristocrats appealed to popular fears to overturn a consensus among their peers imposing limits on reelection to the consulate. Instead, a few men monopolised that office and leadership of the war effort.

In addition, with all these forces operating simultaneously on multiple fronts, overall coordination of strategy, logistics, and recruitment became imperative. Rome had no general staff or high command. The senate filled that role, and the challenge Hannibal posed vastly increased its importance as central coordinator of warfare and diplomacy. Armies also needed to be paid and fed. For nearly two centuries, Rome’s four annual legions had been cheap to run. Now, the enormous increase in its military effort meant a corresponding increase in the cost, which had to be met by the Republic’s taxpayers as well as its allies. And that was not the only increased burden the war placed on civilians. So many men serving in the legions and allied contingents dramatically reduced the manpower left on the small and medium sized farms that sustained the great majority of Italy’s population. Women, children, and older men had to take up the slack. Amid what certainly were great hardships, they grew the food that fed not only themselves but their sons, husbands, and brothers in the armies.

All of these changes and adaptations enabled Rome to withstand Hannibal’s onslaught and slowly pick itself up off the mat. The situation stabilised as the Republic suppressed further defections and went on the offensive where it could. The strategy of attrition enabled it to survive, but not to win – at least in the short term. For Hannibal remained a threat as long as Rome was unwilling to meet him on the battlefield. Finding a way to end to the war meant finding some way to change the balance of forces in Italy. A solution required one further innovation. In 211 the defeat of Rome’s forces in Spain raised the spectre of a Carthaginian army once again marching to Italy and reinforcing Hannibal, undoing all the gains Rome had made there since Cannae. A new force and a new commander were desperately needed, and the choice fell, surprisingly, on a young aristocrat, P[ublius] Cornelius Scipio. The young at Rome waited a long time for a consulate and major military responsibilities, and Scipio had yet to hold any high office or major command. But in this case, the choice was inspired for in Scipio Rome finally found a match for Hannibal. After subduing Spain in a series of brilliant campaigns, he returned to Rome and, having won unanimous election to the consulate, demanded the senate’s permission to lead an invasion of North Africa. Senior members of that body were highly reluctant to break with the slow, grinding strategy that had brought Rome back from the brink and boxed Hannibal in far to the south. Scipio’s strategy moreover represented a major risk, the sort of high-stakes gamble that had gone so disastrously wrong at Cannae. Yet Rome was nearing the point of exhaustion; attrition had taken its toll on the Republic and Italy as well. Bringing the war home to Carthage offered the best chance for ending the war quickly, and that is what it did. Scipio in the end won permission to invade Africa, and his victories there did what Rome had been unable to do in 16 years of war: drive Hannibal from Italy. Scipio’s threat to Carthage compelled that city to recall Hannibal and his army to defend their homeland, surely a bitter blow after all they had achieved in Italy. The two generals finally faced each other a year later at Zama where, after a bloody and hard-fought battle, the Romans crushed Hannibal’s forces, forcing Carthage’s unconditional surrender.

So, what lessons does Rome hold for us today? Obviously, fighting a war in the third century BC is nothing like the struggle against a pandemic in the early twenty-first century. But if there is any conclusion to be drawn, it is that the changes that a disaster compels can sometimes open unanticipated opportunities. For the changes Rome embraced in order to defeat Hannibal revealed a far greater military potential than the Republic had previously realised, a potential that became the basis for a half-century of world-altering conquests. Mass mobilisation, proconsular commands, senatorial coordination of overall strategy, and the civilian population’s ability to sustain that massive military effort all combined to make possible Rome’s ability in the 50 years following peace with Carthage to extend its sway across the length and breadth of the Mediterranean. Naturally, many other factors drove that process forward, and scholars still debate their relative importance. But the catastrophic defeats Hannibal inflicted on Rome forced it to change in ways that made it all possible. Certainly, no one expects COVID-19 to unleash a spate of empire building, but one may hope that it will open an era of conquests that will prove far more beneficial to humanity.

Feature image: The Death of Lucius Aemilius Paullus at the Battle of Cannae, 216 BCE. John Trumbull, 1773. Yale University Art Gallery, 1832.100