Trebia was Hannibal’s first strike against the Romans, and he learned much from it. He realized he could exploit Roman weaknesses with his strengths. He also knew he had to keep the pressure on and move closer to Rome itself. He understood how important his Celtic allies were but knew that their dependability was moot; if he didn’t keep a fast enough pace, his Celtic allies would lose interest.
Even though Hannibal had forced Rome to acknowledge and respect his presence in northern Italy, the Celts were not willing to wait around, especially if the only action was in their own territory. One Celtic motivation was the prospect of booty seized from Romans, both rich territory and the goods that went with it—in some cases, what had even been Celtic lands a few generations earlier. Hannibal had to reckon on Celtic restlessness even in winter, and now that he had changed the terms of ancient battle by fighting in winter, he knew his allied Celts would expect him to maintain this invasion with lightning-strike quickness.
After Trebia, the Roman Senate levied massive conscriptions of plebeians and formed eleven new legions composed of a hundred thousand soldiers.1 Hannibal needed badly to sack Roman allies or find non-Celtic provisions to lessen his dependence on his Celtic allies. It was one thing to be perceived as a liberator, another to be suspected as an occupying force.
Both Polybius and Livy share a bizarre story2 about Hannibal’s relationship to the Celts that modern scholarship has mostly discounted.3 Supposedly worried about being assassinated by the fickle Celts, Hannibal is said to have donned different wigs to disguise himself in case of attempts on his life. But the suspicious incident does not ring true with Hannibal’s position as one who had just beaten the Romans and given the Celtic tribes in North Italy new hope. As one historian sagely points out, Polybius visited a pacified northern Italy at least a generation after Hannibal and the end of the Punic War. Carthage was no longer a threat, having just been destroyed. Polybius would have seen only new Roman settlers felling trees and expanding farms, not a Celtic frontier. The militant Celtic residents had been deported or enslaved.4 Regardless of whether the story about Hannibal is true or not, it speaks to a climate of mistrust between the new allies.
Cremona and Placentia, the two new colonies in the Padana, were Rome’s outposts, vanguards of the inevitable. Rome had to expand by absorbing this region or never feel safe. Rome had felt safe until Trebia. Now it had to prepare for a war on its peninsula, and it made significant efforts to adjust.
Within a few months of Trebia, Sempronius and Scipio returned briefly to Rome, as their joint consulships were finished. Both faced criticism, and Sempronius was, to a degree, disgraced. Publius Scipio would soon reappear in Spain with his brother in ongoing battles with Carthage for the territory north of the Ebro River.5 Hannibal expected a changing of the guard after making several Roman commanders look foolish, but he also knew that the consular rotation could favor him if the Romans continued pairing inexperienced consuls like Sempronius with battle veterans like Scipio. Therefore, he must have instructed his spies to gather as much information as possible about both new consuls.
After occupying Scipio’s former camp east of Trebia for a few weeks—making a statement akin to triumph for the Celts, who could observe the camp vacated by the Romans now filled with their enemies—Hannibal may have paused to harass the area around Placentia.6 But he would not have laid siege to the city, having found out the hard way at Saguntum how drawn out sieges could be.7
Instead of staying near Placentia, Hannibal moved his army east all the way to the Boii tribal territory, the region of modern Bologna, for the next few months. The Boii had been his longest and most loyal allies. They may have been the earliest of the Celts who had sought his help against Rome when he was still in Spain. They were important in his parley with the Celts near the Pyrenees. The Boii had not only given counsel to Hannibal but also had been useful in persuading other tribes to join forces with him.
Finishing his winter with the Boii was not only a way to strengthen Hannibal’s ties to this strong tribe but also a very pragmatic choice. The Boii lived halfway between the new but embattled colonies of Placentia and Cremona and the older established colony of Ariminum, between the mid-Padana and the Adriatic coast. Ariminum was a strong Roman city whose primary role was to guard the easier eastern coastal approach to Rome. Even more important, Hannibal knew from his spies that the Romans had mustered fresh legions under the new consuls and were moving toward him in two directions to attempt to corral him.
Once again Hannibal could count on the Roman system of pairing an experienced military consul with an inexperienced political consul. Gnaeus Servilius Geminus was the experienced one. He reassembled the remnant legions of Scipio and Sempronius at Ariminum. Servilius was tasked to stop Hannibal from marching east to the Adriatic coast. The second new consul, Gaius Flaminius Nepos, a novice at war, moved his two new legions and allies to Arretium (modern Arezzo), facing the southwest flank of the Apennine Mountains that run the spine of Italy, waiting for Hannibal if and when he crossed the Apennines into Etruria (modern Tuscany). Hannibal would not have crossed the Apennines in winter, despite Livy’s account—contrary to Polybius’—that Hannibal made a dramatic but aborted attempt, failing, at great loss, to cross these mountains due to heavy snow and freezing conditions.8
After the winter snows began to melt, the long rains began to diminish, and Italy’s land surface dried sufficiently for an army to move again without becoming mired, Hannibal formed a plan. The two Roman consuls were positioned against the probability of Hannibal moving out from the Boii, either east downriver along the Po to the Adriatic or south through the Apennines.9 Servilius and Flaminius assumed wrongly that they had Hannibal contained.
Yet Rome itself was troubled by fearful rumors and omens, and the transition of consuls had been marked by unusual events. Livy can be counted on to provide drama and color to what was happening in Rome, mentioning omens and prophecies that all seemed to imply chaotic events, many of which were somehow connected to Mars, god of war.10 Roman citizens reported that several Roman soldiers’ javelins had burst into flame, some had seen springs filled with blood, others said the sun appeared to be strangely locked in combat with the moon, or double moons rose in the east by some unnatural optical phenomenon that went against nature.11 For the Romans, who were deeply influenced by divination and whose augurers were treated with great respect, these disturbing omens all suggested that the gods were warning them about chaotic and unusual circumstances, portents best interpreted by those long experienced with reading omens of war. Livy lays much of the blame for the uncertainty and bad omens on Flaminius as a scapegoat for the Roman disaster to come. Unlike Livy, a typical Roman steeped in divination, Polybius is silent about apprehensive omens causing consternation in Rome.
The southerly direction in which Hannibal moved toward Etruria and Flaminius in Arretium may also have had something to do with Flaminius himself. Hannibal seems to have gathered damning evidence about Flaminius. Perhaps for this reason, he decided to march south to Etruria. In any case, a southerly march to Etruria might be more direct and quick if the right Apennine route could be chosen. One historian concludes that Hannibal set out from the Boii in early May.12
Carefully considering his choices, according to Polybius,13 Hannibal led his army south of Bologna over the Apennines and then toward Arretium. The Romans were surprised that he did not take the expected major coastal route but instead chose an interior route to Etruria,14 since the others were longer but obvious to any watchful Romans.
Many historians suggest that Hannibal followed the Reno River and crossed the Apennine Mountains by the low Collina Pass15—only 3,046 feet high (952 meters)—and came down near modern Pistoia, along the Arno River.16 The word Reno derives from an old Celtic word—probably the same Celtic cognate as the Rhine—that means “flowing.” This 130-mile-long river runs southwest almost the full width of the Apennines as it winds like a serpent from Bologna through the twisting valleys until it drops abruptly into the steeper Arno River Valley.
But instead of then heading south or west, Hannibal went east upriver along the Arno marshes, an unexpected transit because it was still flooded with spring runoff from both mountain snowmelt and prolonged rainfall. This may have been a slightly more direct route if dry, but with its waterlogged terrain, it was hazardous. Hannibal must have had Boii guides who knew this route. Believing the Arno route to be impassable at this time, the Romans (or at least Flaminius)17 were unprepared for Hannibal to come toward them from the northwest.
While not as famous as his Alpine march, Hannibal’s four-day trek through the Arno marshes was perhaps equally terrible in other ways. Both Polybius and Livy recount the slow suffering of Hannibal’s army on this long, unhealthy, and even life-threatening slog. Swamp conditions must have been much like those described in Dante’s Inferno of the River Styx, sluggish with stinking mud and swarms of mosquitoes and other voraciously biting insects breeding in the stagnant water.
At first, Hannibal’s army was unwilling to follow him into the Arno marshland. But he left no room for alternatives and placed his troops in a very deliberate order. In the front, he positioned his Spanish infantry and Africans, followed by his ally Celts in the middle, and his cavalry at the rear under the leadership of his brother Mago. He also distributed his pack animals in every location throughout the long train in order always to keep food at hand.
Hannibal sandwiched the Celts in between trustworthy troops because he could not trust the Celts to stay the course. If they thought they could melt away at night, Hannibal outwitted them. If the unruly Celts stopped or tried to turn back—they could hardly fan out sideways into the mired swamp—Mago’s cavalry would block their escape and prod them forward—or threaten to ride roughshod over them. They had nowhere to go but forward.
These details in Polybius’ history18 suggesting previous Celtic intransigence must have happened enough times for the Punic veterans to force the Celts to stay mostly in line. But this strategy would have only increased Celtic sullenness and made many less likely to stay with Hannibal once the marsh was traversed. There must have been growing Celtic resentment against Hannibal because they always fared the worst of his army in every phase of his campaign. But no one could ever accuse the Celts of not being brave in battle. Their frenzied battle preparations bordered on a mix of hyperactivity and intense bravado.
On the other hand, Hannibal’s placement of his troops also shows how much he respected his own well-disciplined men who had been with him since Cartagena and had already survived great hardships. It was increasingly obvious that because his supply lines back to Spain were gradually reduced and cut off by the Romans, Hannibal had to depend more and more on Celtic allies, which was not an ideal war plan. The Arno marshes would test the Celts’ loyalty to the limit. At least one historian suggests this was deliberate on Hannibal’s part to weed out the weakest Celts and harden the remaining ones.19
Even the usually terse Polybius describes graphically the harsh conditions in the marshes, as soldiers endured water up to their knees or higher, with sucking mud underneath.20 It was impossible to set up camp21 in the shallow water and mud, so the army struggled for four days essentially without sleep. The energy expended would have led to utter exhaustion, since so much effort was needed to make forward progress. The heavily laden pack animals fared horribly and died where they fell in the mire, probably in many cases unable to pluck their feet from the muck and unable to rise from the gluey mud. The pervasive wetness also soaked into and rotted their hooves. Expendable beasts of burden, the baggage animals mostly perished. Hannibal seemed not to mind the staggering loss of animals because he knew supplies would be plentiful when they reached rich Etruria. The variable quantity of Hannibal’s pack animals over several decades, however, was an exigency of war in enemy territory that ultimately would prove insurmountable.22
Conditions were so bad in the marshes that the mired animal carcasses provided the only relative dry spots on the nearly continuous march. The men could pile whatever they could on the partly submerged dead animals and try to catch a few minutes of sleep whenever possible perched above the water. But even these would be only the shortest of intervals, never much more than nodding off and resting strained muscles when the bunched troops simply could not move forward and the long line temporarily came to a logjam standstill.
As usual, Livy adds extra color, saying that the Celts had to be guarded as they “lived up to national character” by their unwillingness to pass through the marshes except by the rear force of Numidian cavalry pushing them onward.23 Describing the many deaths as miserable, Livy also claimed that the major contributing factor to the loss of life was lack of sleep for successive days, and he suggests the water level was up to the men’s necks at times and that flood eddies near the Arno River also pulled men in and drowned them. Naturally, Hannibal would have kept as many men as possible in the shallower water.
At night, the marching conditions were even worse. And the smell of the stagnant water would also have been chokingly oppressive. Conditions were ripe for water-borne infections and septicity. Anyone already suffering from tuberculosis would have likely succumbed to the omnipresent seeping damp that penetrated infected lungs. The cold mud would only have gotten heavier, and the cold water would have dissipated body heat as well. Furthermore, the moans of animals dying prolonged deaths, and the coughing of sick or feverish men would have been a living hell, nightmarish especially in the dark. No fires could be lit other than torches to show the shadowy way. The soldiers would have even fouled their own passage, exacerbating the stench and unhealthiness. Cholera was an ever-present danger in such circumstances of compromised drinking water. Carrying an adequate supply of fresh water could only have become increasingly harder. Like Samuel Taylor Coleridge’s The Rime of the Ancient Mariner (“Water, water, everywhere, and not a drop to drink”), dehydration from lack of potable water in the swamp only worsened the army’s overall spirits.
This marsh passage would have haunted many who survived, and while Hannibal’s iron will pushed them forward relentlessly, he too must have wondered if they were ever going to get out. No doubt he constantly grilled his Boii guides and forced himself to stay alert and set a good example, but Hannibal too would have been greatly fatigued because he could not relax his leadership while the army had such a difficult time making forward progress. Protracted sleep deprivation, exhaustion, and the endless damp all compounded to take their hellish toll not only on men and animals but also on their leader.
In the Arno marshes Hannibal contracted an eye disorder that caused ophthalmia, or inflammation of the eye or eyelid. In four days, before he emerged from the marsh, he lost the sight in one eye. Livy blames the eye problem on temperature fluctuations between heat and cold in the early spring variable weather.24 While it is unknown what the agent of infection might have been, some logical guesses range from an aggressive conjunctivitis caused by detritus in the eye, to bacterial or viral infection from swamp microbes such as bacterial Staphylococcus or waterborne Pseudomonas aeruginosa and Acanthamoeba.25 Medical treatment—for example, irrigating with clean water and an herbal poultice—was impossible given the surrounding swamp water and the length of this debilitating march. (A curious footnote to history is that the Romans seem fascinated with one-eyed enemy generals. Other warrior kings assembled against them were similarly afflicted.)26
Not only did Hannibal lose an eye in the Arno marshes—although some say he lost only partial sight27—but also his war elephants were reduced to the single elephant that he rode personally. According to Cato the Elder as recorded in Pliny,28 this was likely an Asian elephant named Suros (“Syrian”) that may have had one broken tusk.29 One famous phrase that now identified Hannibal to not only his Carthaginians and allies but also to his enemies was “A one-eyed general riding on a huge Gaetulian bust [elephant].”30
Possibly emerging from the marshes east of Faesulae and modern Florence,31 Hannibal’s waterlogged army could stretch out at last on dry ground, camping for a few days to rest and then continuing unmolested in either a southerly or southeasterly direction.32 Although he could still bypass Flaminius at Arretium, Hannibal could raid the rich farmland along the way and replace the dead pack animals and grain, some of which had spoiled with fungal molds in the Arno marsh.
The Celts were thrilled finally to pillage someone else’s territory, as this had been nominally Roman since the late fourth to early third century BCE when Rome had broken the Etruscan and Samnite holds on the region.33 One historian says that by marching into Etruria, Hannibal hoped to exploit Etruscan resentment against Rome, as he had with the Celts, in order to gain Etruscan support against their Roman overlords.34 Hannibal’s Celts now glutted themselves at last on Roman bounty, returning the favor on those Roman legions that had earlier stripped Cis-Alpine Gaul. Hannibal probably did little or nothing to curb the impetuousness of his Celts in their payback to Rome. At the same time, he replenished his supplies and pack animals, especially mules, with the provisions his army needed badly, all the while able to move successfully behind Flaminius’ back.
Hannibal’s swampy trek caused him considerable losses, a seemingly reckless choice of route, given the deaths of Celtic allies and most of his pack animals. The spring of 217 could have been a complete disaster for Hannibal. The element of surprise would work only if Hannibal retained enough of his army and Flaminius had no time to prepare for a showdown against Hannibal. Evidently, Hannibal had much better information and network of informants within the Roman army than Flaminius had of the Punic forces.
Hannibal had to have been doubly relieved. Not only had his army of disciplined veterans survived the Arno ordeal, but also the allied Celts could at last seize the booty he had promised to gain them as allies. Perhaps the best way to judge Hannibal’s costly Arno marsh crossing is to note that he emerged where Flaminius wasn’t looking for him. This part of his plan succeeded. Hannibal had now just turned thirty years of age, no longer young but a man nourished by war since childhood. His greatest battles were yet to come. Even in Livy’s mostly unsympathetic eyes, Hannibal approached the Roman heartland as a heroic yet tragic figure.