Hannibal moved very fast much of the time. Part of his speed of travel was necessary because he could ill afford to fight a larger enemy on its home ground too many times; battle attrition would become desperate with his relatively small army and dependence on Celts. His army had to hope to seize much of its supplies on the fly rather than have too long a train of slow pack animals, easily caught by the Romans.

Hannibal’s decisions in Etruria and his prebattle moves were contingent on the character of Flaminius.4 Whether Hannibal allowed little plundering through the Apennines and his first emerging into the Arno Valley—our sources are silent about it—such a decision would have been sensible because this kind of word spreads fast in relatively well-populated regions such as Etruria and would have revealed his movements en route to the Arno Valley. After the Arno marshes, however, Hannibal seems to have done little to keep his whereabouts secret. His actions may even have been provocative. Perhaps his plan was already laid to trap Flaminius in a place of his choosing. Moving south through the Val di Chiana in central Italy, Hannibal made it appear he was heading toward Rome.5

Surprising Flaminius, Hannibal continued quickly south beyond Arretium to the northern edge of Lake Trasimene and the hills above it. He had formed an audacious plan that would again require the help of nature as well as the impetuous Flaminius. It is vital to understand what Hannibal now knew about Flaminius.

THE CHARACTER AND CAREER OF GAIUS FLAMINIUS NEPOS

Gaius Flaminius Nepos was already a man of contradictions and controversy before Trasimene, an arriviste with minimal history and a lot to prove, ready to risk everything to advance his career. The Romans call this kind of person with no patrician tradition and no family history in the Senate, a novus homo, “a new man.”6 Like other new men without noble ancestry, Flaminius was seemingly the first in his family to enter the ranks of the cursus honorum,7 or the “course of offices,” as a high elected official, leading ultimately to the Senate. Such advancement was rare at the time but possible, especially after 287 BCE, when the last patrician check on the Plebeian Council was lost, and the plebeians gained political equality.8

But in his case, Flaminius was entirely the beneficiary of the plebeian vote, not patrician backing. He had been a censor9 and a tribune of the plebs and a plebeian consul just a few years before, in 223. His being a novus homo alone would immediately put him at odds with the majority of patricians in the Senate, but his flamboyant disregard for custom and his quarrelsome individuality were the deeper roots of his political problems. He regularly challenged the authority of the Senate, which naturally endeared him to the commoners.

While tribune of the plebs in 232, Flaminius helped pass a popular land reform that distributed recently conquered Etrurian land south of Ariminum to the poor, who had lost much during the war. Naturally, the Senate opposed this, but he did not consult them—a severe breach of custom and the Roman constitution. Flaminius had also greatly angered the patricians in the Senate in 218 by being the sole vote in support of the Lex Claudia law which was intended to stop senators from profiting from commerce abroad. He felt that they were already wealthy enough and believed this practice was a conflict of interest for those who govern. He overstepped his authority by trying to rein in the powerful Senate and was voted down vehemently.

During his censorship of 220 BCE, Flaminius had been responsible for creating and constructing a major trunk road north from Rome, through Umbria, to Ariminum. This was the famous Via Flaminia, one of the oldest Roman roads and duly named after him, crossing the Apennines considerably east of Arretium, a course of 210 miles (329 kilometers). Flaminius was very proud of this success, and to be fair, his leadership had some administrative and financial merit. But this is quite different from good military strategy.

As a patrician himself, Livy was scornful of Flaminius, deeming him unworthy of the office of consul for his multiple infractions. Just like a politician—exactly what Flaminius was—whose acute sensitivity to popular support made him often reactive rather than proactive, Flaminius sought every expedient opportunity, however ultimately foolish, to please his power base among the plebeians rather than appease the Senate. He knew he had no other means of support, unlike his wealthy patrician counterparts, who were landowners or had other commercial bases of power.

But as consul, he went quietly and directly to Arretium as a private citizen would, ignoring all the requirements incumbent on an office-holder before taking such action. This was outrageous to the Senate, and his colleagues promptly recalled him, to be dragged back if necessary. Flaminius ignored the Senate’s messengers. This defiance was unprecedented. Livy says the Senate angrily proclaimed, “ ‘Flaminius’—such was the cry—‘is now at war not only with the Senate, but with the gods.’ ”10

Flaminius had justified to himself that the patricians in the Senate would have delayed him, either to falsify the auspices or tie him up with petty duties that took too much of his time. We don’t know whether the Senate fully understood his character, hastiness, and military inadequacy, but it is possible that they wanted to observe him and gauge his readiness, given the recent military setbacks at Ticino and Trebia. But Livy relates that an animal being sacrificed in the presence of Flaminius—presumably at Arretium—leapt from the altar, escaping before the deed was finished and spattering blood all over the bystanders. This was apparently interpreted universally as “an omen of coming disaster.”11 Livy may have been implying the coming defeat of Rome as a result of Flaminius’ hubris and a divine act. He set up Flaminius against Hannibal: doomed before the battle began.

While not everyone blames Flaminius entirely,12 Livy was not alone in his low opinion of the consul. Here’s what Polybius says about Hannibal’s discovery of Flaminius:

He learned that Flaminius was a thorough mob-courtier and demagogue, with no talent for the practical conduct of war and exceedingly self-confident. Hannibal calculated that if he passed by the Roman army and advanced into the country in his front, the Consul [Flaminius] would on the one hand never look on while he [Hannibal] laid it waste for fear of being jeered at by his soldiery; and on the other hand he would be so grieved he would follow anywhere, in his anxiety to gain the coming victory himself without waiting for the arrival of his colleague [Servilius Geminus]. From all this he concluded that Flaminius would give him plenty of opportunities of attacking him. And all this reasoning on his part was very wise and sound.13

The modern consensus is little different: Flaminius was rash and imprudent, and Hannibal had accurately assessed the man.14

LAYING THE TRAP FOR FLAMINIUS

Ever ready to cite divination as predicting human folly, Livy relates two more omens that spooked Flaminius’ officers as he set out to chase Hannibal with his army. First his horse threw him, and then one of the legionary standards, a metal pole with an eagle and legion ID, was stuck in the ground. No matter how hard the standard-bearer tried, he could not budge it. Livy puts these words in Flaminius’ mouth: “Tell them to dig it out if they are too weak with fright to pull it up.” Flaminius’ lack of humility stands out glaringly in this anecdote. He marched off without first sending his scouts to ascertain the situation. This must have agonized his officers, who knew better. Did Flaminius just rush out without giving his army adequate opportunity to verify where Hannibal was going?

By now it was mid-June. Making sure that Flaminius was following him and could see his movements, Hannibal turned east at the north end of the lake toward Perusia (modern Perugia) instead of south toward Rome. Timing it perfectly, when daylight was finally fading, the last of Hannibal’s army disappeared into the very narrow Borghetto gap between the north end of Lake Trasimene and the steep hills of Cortona. The army of Flaminius had followed Hannibal from a modest distance, arriving at sunset, as Livy noted,15 but the Roman army pulled up short as night began to fall. The soldiers could probably even see Hannibal set up camp at the far end of the lakeside valley. They would camp and pick up Hannibal’s trail the next morning. Looking into the small valley through the Borghetto gap, one can still see at summer dusk—as I did—the last glow of sunset on the hills above even as the little valley is in the dark shadow of the high hills.

But that night, Hannibal shifted his men around to several locations. Under cover of darkness, portions of his army were split up and posted in several of the steep ravines whose streams fed the lake from the north. Had Flaminius’ scouts reported anything, they would have seen only the red glare of the high number of army campfires clustered together in the distance.

The Romans apparently didn’t notice the hidden movements of whole units of thousands of men and horses in the dark, most of them moving upward along the heights of the ravines above the small plain. Hannibal would have demanded stealth and quiet for this maneuver and few if any torches to show the way. Hannibal secreted his Numidian cavalry in the western hills nearest the Borghetto gap. He hid his light infantry of pikemen and Balearic slingers in the hills near modern Tuoro, above the lakeside route. Then just eastward, next to the light infantry, he hid his Celtic allies. Finally, his many units of Africans and Spanish heavy infantry stayed close to his camp in the east of the valley, the only ones who might have been visible the next morning. Polybius states that Hannibal’s army units formed a continuous line under the hills,16 albeit much hidden, so they would be roughly parallel to the lake’s northern shore except at the very end of the lake.

That night, Flaminius’ wary officers must have been telling him not to advance but to wait for Hannibal either to come out or for the army of the coconsul Servilius to arrive from Ariminum with an array of several legions he commanded, as he would have heard by now of Hannibal’s movements in Etruria. But Flaminius overruled them.

THE BUGLES OF BATTLE, HORNS OF DEATH

When the next morning dawned, nature could not have been more accommodating for Hannibal’s trap. Some ancient poetic sources such as Ovid (a Roman poet of the Augustan Age 43 BCE to 17 CE) say it was the summer solstice, June 21,17 and Hannibal may have already seen in previous days a common local summer phenomenon when a warm air mass over land meets the much cooler air mass over a body of water: fog was thick along the north shore of Lake Trasimene, noticeably hemmed in by the steep hills. Whether or not Hannibal anticipated the early morning fog, he certainly used it to his advantage. Much of his army was invisible in either the foliated hilly ravines or the early-morning fog that hung thick in the valley.

Livy says that Flaminius sent no reconnaissance whatsoever ahead of him. Many have wondered why Flaminius did not send advance scouts into the narrow Tuoro plain before he raced his army through the narrow valley opening.18 Was Flaminius that foolhardy in a makeshift battle plan?

If Hannibal on higher ground saw or heard Flaminius’ vanguard pouring without hesitation into the gap at first light, he then knew his plan would work. He waited until the Roman army advanced in formation all the way to his front line of African and Spanish infantry. Then the war bugles gave the signals with their prepared sounds. The echoing call from all sides across the valley must have bewildered the Romans, surrounded as they were now in soupy fog.

Hannibal’s cavalry descended downhill behind the Romans and cut off any escape by sealing off the Borghetto. Now the Romans were in a gauntlet: Hannibal’s army attacked on three sides, with the lake to the south, likely in a line that stretched at least full four miles of the Roman column.19 Here Hannibal used the marshy lake edge as part of his arsenal. Hannibal’s separate forces seemed to have hit the entire Roman column simultaneously,20 and the unready and totally surprised Romans had no time to change from marching formation to battle formation. A terrible onslaught came at them out of the fog with a roar—especially the Celts—and the thunder of horses. The Balearic slingshots pummeled the Romans, as did spears and other projectiles, appearing from nowhere, possibly before the Romans had their shields up.

The Romans fought bravely, and the fighting was fierce, but it was nearly a fait accompli. The sounds of battle came from everywhere in the fog, and the Romans would not have seen much of the enemy until it was upon them. No matter which way the Romans turned, death came from everywhere, and they were “cut down in their marching order,” Polybius claims.21

Due to the fog, the sounds of battle—with thuds of blows, metal on metal, shouts, screams, and groans—would have been more apparent than visual evidence. This would have been part of the ethos of chaos intended by Hannibal and would have been much harder on the regularized formations of Romans than on Hannibal’s army, especially his Celts, who championed individual hand-to-hand combat rather than close-knit organization. The fog hampered the efforts of Roman officers to turn rank and file into battle formation. It continued to stymie officers’ commands to regroup if they could barely see one another, let alone the enemy. Many Romans must have fought valiantly, especially the veterans, who were trained to fight to the death. Their tragedy is due mostly to Flaminius’ poor leadership, as Polybius says, “betrayed by their commander’s lack of judgment.”22 Livy claims nobly that their one hope of life rested in their swords, ultimately dependent not on their officers but on their individual will to fight, however futile, but he may have been only putting a good face on one of the biggest ambushes in ancient history.23

If Hannibal’s army had little visibility in the fog, at least it had the advantage of controlling the direction of the battle from the outset, whereas the Romans, individually and collectively, were caught in the vise of an attack that compressed them on all sides, with the only stationary force—the lake—being equally perilous. If the Romans backed too far into the water, some effects of hypothermia—such as the draining of body heat—would slow them down even more. Retreating up to their necks to escape, many Romans drowned in their heavy armor. Numidian cavalry were waiting wherever they might attempt to come ashore. Polybius says that many Romans surrendered in the lake, with only their heads above water, lifting their hands as they pitifully begged for mercy but were hacked down anyway.24 The slaughter of Romans was everywhere: on the road, in the plain, and in the lake, whose lapping shallows were tinted with the blood of the Roman dead.

The battle lasted most of the morning—“three long bloody hours” as Livy puts it.25 If there were an epicenter, it would have been around Flaminius. While Polybius denigrates Flaminius as being most dejected and filled with the “utmost dismay,”26 and possibly dread at finally seeing his folly, Livy claims instead that he was moving about trying to help any Roman with a core group of his best men, who were “as determined to save him as the enemies were to kill him.”27

But Flaminius was conspicuous in his ornate consular regalia and equipment, no doubt also surrounded by the glint and color of legionary standards, and this eventually was a magnet for enemy attention. At the heart of the battle, one Insubres Celt warrior on horseback, possibly a leader named Ducarius,28 recognized Flaminius and spurred his horse forward into the thickest battle frenzy, crying that he would sacrifice the consul to the Celts whom Romans had turned into ghosts. This was a normal Celtic action, looking to be a champion with a glorious kill of an enemy commander. He rode with furious abandon over Flaminius’ armor bearer and with great force impaled the consul with his lance, driving it through his body with his momentum. Flaminius dropped like a stone. His men surrounded him with shields to protect him as he lay dying, even as the Celtic lancer may have tried to take a trophy by stripping him of a piece of consular regalia such as his plumed helmet.

News of Flaminius’ death spread faster than an official command and sent the surviving Roman army into final panic. Such an important death invigorates one side in battle just as it fills the other with dread, a now-headless army. The panic was probably exacerbated by the fact that, as one historian points out, many of these soldiers had already witnessed Hannibal’s tactical surprise at the Trebia River in 218.29 They had witnessed one impetuous general in Sempronius and now likewise in Flaminius.

One group of six thousand Romans at the front, however, had fought its way out, and when the soldiers could see nothing due to the fog, they climbed to a spur over the valley. But when the sun’s heat on this June day finally dispersed the fog, it was clear that the valley was filled with Roman bodies piled everywhere. Hannibal’s army was gathering groups of prisoners who had surrendered or were too wounded to fight. Reminders of the Roman bloodbath are still found today in relict names of local streams such as the Sanguineto (bloody place).

The isolated six thousand Roman soldiers who had escaped the slaughter were soon surrounded in a village where they had fled. Maharbal, Hannibal’s Numidian cavalry commander, and Spanish infantry and pikemen had noticed them fleeing and soon found them. The Romans surrendered, thinking that if they abandoned their weapons their lives would be spared. But Hannibal freed only the Romans’ Celtic allies, sending them to their homes with the astute propaganda of claiming their enemy was not him but Rome.

The number of Roman deaths at Trasimene is stated at 15,000, with an equal number of prisoners, including the wounded. This is as much as a 75 percent loss,30 a staggering quantity for an ancient battle. An entire Roman army of at least around 40,000 men was reduced to only the 6,000 soldiers who escaped in disorder as the broken fragments of several legions. One of the ironies of this battle is that Flaminius had brought hundreds of manacles and chains31 to carry off Hannibal’s army as slaves to Rome. Now their own chains must have bound them as they were taken captive prisoners of Hannibal. Hannibal lost a tenth of the number of Roman deaths—about 1,500, according to Polybius—although Livy claims 2,500 enemy dead,32 mostly the Celts who had been at the direct center of the Roman column that had fought first and probably last.33

The Romans protecting the body of Flaminius must have also soon perished because after the battle, Hannibal tried to give Flaminius a decent burial, but the body could not be identified on the battlefield. Flaminius’ corpse had been likely stripped of armor and regalia and maybe decapitated in Celtic fashion. This possible decapitation was eerily symbolic of the now-headless Roman army at Trasimene.

The disaster of Trasimene was followed immediately by another awful setback. Up north, Servilius had by now heard that Hannibal was in Etruria and had sent four thousand cavalry from Ariminum to help Flaminius. He planned to follow soon with his full army, hoping to intercept Hannibal, possibly to march south along the Via Flaminia34 so that he and Flaminius could bottle up Hannibal between them. Perhaps Servilius thought that together they could set up Hannibal in a trap, when it was the other way around.

Hannibal’s informants who had been watching Ariminum told him of the cavalry force, and Hannibal immediately sent out Maharbal with some Numidian cavalry and pikemen. The more mobile Punic force caught the Roman reinforcements unprepared, slaughtered half, and took the remainder prisoner the next day. Three days after the battle at Trasimene, this action added another two thousand Roman deaths and an equal number of Roman prisoners carried away, an unheard-of catastrophe for a standing Roman army.35

The dire double news of the Trasimene defeat and of Servilius’ reinforcements took Rome by utter surprise. The shock waves reverberated throughout Italy. According to Livy,36 common citizens flocked en masse to the old Roman Forum, and the capital suddenly swelled with crowds who’d left their homes and gathered, filled with the dread of rumor. Wailing women waited at the city gates hoping to hear news of surviving loved ones. The crowds became so great that the Senate had to respond. The quaestor (a Roman magistrate, lower than praetor, involved in the treasury) Marcus Pomponius announced in the most laconic utterance, “We have been defeated in a great battle.” Other praetors (an elected high Roman magistrate, sometimes legionary commanders of past armies) of the Senate forced the whole assembly to sit for days from dawn to dusk and debate who would succeed to restore leadership to the legions.37 Trasimene was a true defeat, as the quaestor acknowledged before the assembled people of Rome; the most serious crisis possible.

Again, as at Trebia, Hannibal used nature—the lake and the fog—as a weapon of war, virtually as effective as a whole new army. Hannibal had achieved something unprecedented. He seems almost to have invented environmental warfare. Having incorporated it into his battle plan, he would be emboldened to use nature again.