Roman Meets Gaul


The initial Celtic inroads into northern Italy may have been peaceful but after 400 BC they turned violent. Calls for war and raids were proclaimed during banquets like the one described in the writings of Athenaeus.

“When several dine together, they sit in a circle; but the mightiest among them, distinguished above the others for skill in war or family connections, or wealth, sits in the middle like a chorus leader. Beside him is the host and next on either side the others according to their respective ranks. Men-at-arms, carrying oblong shields stand close behind them while their bodyguards seated in a circle directly opposite, share in the feast like their master.”

Probably present too at these Celtic councils, were their priests, the druids, whose creed even at this time was considered ancient and whose origin may have dated to proto-Celtic times.

The lands and cities north of Etruria, belonging to a mosaic of peoples, were steadily looted and annexed by waves of Gallic tribes. Circa 396 BC Melpum fell to the Insubres and five years later, the Boii sacked the Etruscan colony at Marzabotto. In 391 the Senonian chief Brennus led large bands of Gauls into Etruria proper and threatened the town of Clusium. With no help forthcoming from the other members of the politically divided Etruscan cities, Clusium appealed to Rome for help.

In response to Clusium’s pleas, the Roman Senate sent envoys, the sons of the influential patrician (aristocrat) Fabius Ambustus, to forewarn the invading Gauls. The envoys came in peace but tempers soon flared. The Gauls stated that they had no quarrels with the Romans but when asked as to what right they had to the lands of the Etruscans, the Gauls replied “that they carried their right in their weapons … and that everything belonged to the brave.” The Fabii, the sons of Fabius, saw that the proud Gauls had no intention of leaving the Clusians in peace. Eager to test the haughty barbarians’ mettle, the Fabii incited the Clusians to sally out against their besiegers. In the engagement one of the Fabii ran his spear through a Gallic chieftain. Whilst the Fabii despoiled his slain foe of his armor, Brennus saw him and swore upon the gods that, contrary to holy practice, an ambassador who allegedly came in peace had taken up arms with the enemy!

Flabbergasted by the actions of the Fabii, the Gauls retreated from Clusium in order to debate on the Roman intervention. Boiling with anger, some called for an instant advance on Rome but the cooler heads of the elders counseled that ambassadors should be sent first. The elders had their way and the Gallic envoys stated their case in front of the Roman Senate: war could be avoided if Rome surrendered the Fabii ambassadors.

The Senate appreciated the validity of the Gallic demands as did the Fatiales, the priestly guardians of peace. The father of the Fabii brothers, however, had more pull among the masses than either the Senate or the Fatiales. More popular than ever, the warmongering Fabii brothers were even elected as consular tribunes. The consular tribunes in essence shared the power of the former Roman King and the command of the army. To the Gauls this was a slap in the face. The envoys threatened war and returned to their people.

Soon messages from Clusium arrived at Rome: the Gauls had arisen in rage and with celerity stormed southward against Rome. In fear of the Gallic hordes, cities shut their gates while the rural folk took to flight. But for the most part, the Gauls spared the countryside of Rome’s neighbors. Their quarrel was with Rome. Everywhere they went, the Gauls shouted that they were going to Rome. Despite all this the Romans remained complacent. Although alarmed by the speed of the Gallic advance, the Roman commanders were sure that they could handle the barbarian rabble. An army was hastily raised by a levy. Less than eleven miles from Rome, the Romans intercepted the Gauls on 18 July 390 BC on the left bank of the Tiber near its confluence with the River Allia.

Whatever their preconceptions, the Romans were shocked at the sight of the Gallic army. Here was no orderly phalanx confronting them, but a well over 30,000-strong mob, of tall, big-boned men. The Gauls smeared their long curly hair with thick lime wash, and swept it back from their forehead like a flying horse’s mane. Their faces sported full mustaches which drooped down the sides of their chins. Torcs of gold, electrum, silver and bronze, akin to magical talismans, adorned their necks. Some warriors may have stripped completely naked, in accordance with religious and social customs. Others bared only their upper body or wore a tunic alongside their trousers, both of colorful checkered or striped patterns.


The bulk of the Gallic warriors fought as light infantry swordsmen. The early Gallic iron long-sword measured 25 to 30 inches overall. The double-edged blade ended in a pointed tip and judging by archaeological finds was of superb quality. On the other hand, the Greek historian Polybius described Celtic swords as “effective only on the first blow; thereafter they are blunt, and bend so that if the warrior has no time to wedge it against the ground and straighten it with his foot, the second blow is quite ineffective.” Other weapons were spears, at times over 2 yards long, javelins, battle-axes and slings.

For most warriors their sole protection was their shield. Those of the infantry were shaped as yard-long, oblong hexagons or truncated ovals. Cavalry shields were commonly rounded. Bronze, or rarely iron, helmets resembled jockey caps and were festooned with horns, crests of animal designs or the Celtic symbol of war, the wheel. Rarest of all was body armor, reserved for a few of the chiefs and noble warriors who boasted mail shirts or round breastplates and even the occasional piece of armor for their horses.

In pompous displays, nobles arrived at the battle site in chariots but chose to fight the actual battle on foot or mounted steeds to lead the cavalry. Howls and wild cries, accompanied by the blaring of horns and trumpets, resounded over the battlefield as the Gauls worked themselves into a battle frenzy.

Upwards of 15,000 Romans and allies from neighboring Latin cities faced the Gallic horde. The Roman units were concentrated into the “Legio”, a levy “gathered from the clans”, of 6,000 warriors blessed by Mars, the Roman god of war. Tactically the Legio relied on the shock value of a phalanx of hoplites (heavy infantry). The hoplites were ideally armored with helmet, breastplate, greaves and a round shield, the clipeus, affixed to the forearm. They were armed with a thrusting spear and a sword. The legionaries were drawn from Rome’s citizens. Hoplite tactics were widespread throughout Greece and Etruria and were introduced from Etruria into Rome during the mid-sixth century. In addition to the heavily armed hoplites, the legion also included light troops and was further supplemented by some 600 Roman cavalry.

Despite the superior numbers of the enemy, the Romans made no attempt to fortify their position. To prevent being outflanked by the Gauls, who had formed a broad front, the Romans greatly extended their wings. The extra men required for this were apparently taken from the Roman center, which was thus weakened. Even so there were insufficient men to make the Roman front equal to that of the Gauls. As a result the Gallic army not only extended beyond the wings of the Romans but, on the average, was twice as deep and even more so opposite the Roman center. To the right of the Romans there was a small hill and here the Romans stationed their reserves. They were the weakest troops in the Roman force, poorly armed and inexperienced.

Brennus, the Gallic chieftain, suspected that behind the scanty numbers of the enemy lurked some Roman ruse. He feared that the Roman reserves on the hillock would outflank his left wing and strike at his army from the rear while his men were engaged with the legion. As a result Brennus opened the battle by attacking the reserves with elite detachments, possibly cavalry, from his left wing.

The drone of trumpets blared across both sides. From the higher ground on the hillock, the Roman reserves managed to hold out for a while. But then the brute power of the barbarians proved too much. Some of the reserves were driven back into the hills while others were pushed onto the main Roman battle lines.

Upon the rest of the Roman army the shouts and clamor of battle on the hill had a disastrous affect. Not only was the Roman right wing and center thrown into confusion but panic spread from those nearest to the reserves, like a domino affect, all the way across the lines. At this moment the whole Gallic army charged. The ferocity and momentum of the barbarians completely shattered the Roman phalanx. The Gauls could scarcely believe their good fortune. “None [the Romans] were slain while actually fighting; they were cut down from behind whilst hindering one another’s flight in a confused, struggling mass,” wrote Livy.

The Roman left wing and possibly the entire center were swept into the Tiber. Along the banks of the river, there was a great slaughter. The Gallic longswords hewed down upon the Romans like butcher’s cleavers. Many legionaries tried to swim across the river, but the current sucked down those too wounded or unable to swim or those too hampered by the weight of their cuirasses. From along the banks, the Gauls peppered the swimmers with missiles. The Romans who reached the other side fled to entrench themselves at the deserted site of Veii. On the Roman right wing the situation was much better. Instead of fleeing toward the river, the majority of the legionaries retreated into the hills and then to Rome. In Rome they fled up to the Citadel on the Capitol Hill but were in such haste that they neglected to close the city gates.

The Gauls were astonished by their easy victory. They piled up the enemy weapons in great heaps as an offering to their gods and decapitated their fallen foes. Grizzly trophies dangled from bloodied hair, tied to Gallic spears, chariots and horse harnesses. The time of the battle was just after the summer solstice. At night, like some baleful eye, a nearly full moon shone upon the grim field of slaughter.

The next day the Gauls set off towards Rome. The sunset painted the horizon red as the Gauls tramped up to the city gates. Ahead of the main Gallic host the cavalry had carried out reconnaissance. To what must have been an astonished Brennus, the cavalry reported that they had encountered no enemy pickets, that the gates to the city were not shut and that no troops manned the walls. Suspicious of the virtually effortless way they had defeated the reputable might of Rome, the Gauls suspected a trap. Instead of marching right into the undefended city, they bivouacked between Rome and the nearby River Anio and sent further patrols to reconnoiter the walls.

Within the walls of Rome, the wailing and lamentations for the fallen at the River Allia were replaced by a silent terror of the enemy. Throughout the night, the yells and galloping of enemy cavalry could be heard outside the city walls. For those inside the city the tension was nearly unbearable. But due to Gallic indecision, no attack came during the night.

The citizens decided that the city itself was doomed. There was a lack of fighting men and the walls, which consisted of little more than an agger (earth rampart) and a ditch, were wholly inadequate. The only defendable spot was the Citadel on the steep Capitol Hill, where the Senate and the men of military age, along with their families, sought refuge. The priesthood fled from the city, taking with them the most sacred religious relics. As to the common folk, the plebs, many followed the priests’ example and streamed out of the city in unorganized mobs to seek safety in the countryside or within neighboring cities.

About three days after the battle at the River Allia, the Gauls entered the city unopposed. Although they had carried out nightly cavalry reconnaissance, they could not have been very thorough. The Gauls were surprised at the large number of people who, along with their possessions, had already slipped through their grasp. The Gauls stationed a squad of troops around the Capitol Hill, and then, like frenzied wolves, let loose their wrath on those that remained behind or on those who were still in the process of fleeing. For the next few maddening days and nights, the Romans on the Capitol watched helplessly as below them their cherished city was torched. From out of the roaring inferno, as from the fiends of hell, resounded the bellow of the barbarians and the pitiful cries of citizens put to the sword.

After nothing survived amidst the ashes and ruins, the Gauls stormed the Citadel. In stark contrast to the battle of Allia, the Romans now put up a stout defense. The Gauls came on with a battle-shout and locked their shields above their heads to protect themselves against missile fire. The Romans let the enemy advance about halfway up the hill to where the ground was steepest, and then charged. Because of the steep gradient the Romans proved unstoppable and completely scattered their foes.

Wisely deducing that any further attempts to take the Capitol would be fruitless and only result in more Gallic casualties and that in any event time was on their side, the Gauls surrounded the Capitol in a blockade. The problem was how to feed their own troops since the fire had burnt the grain supplies in the city and the surrounding fields had been stripped bare by fleeing citizens. The Gauls decided that half of their numbers would scour the countryside for provisions while the other half continued the siege.

At Rome, a period of relative calm set in. The Romans remained secure within their hilltop fortification while the besiegers continued their investment. Elsewhere there was more activity. At the city of Ardea the Roman general Marcus Furius Camillus, the renowned conqueror of Veii, rallied the citizens against Gallic raiding parties. Not far from Ardea, they surprised and slaughtered a large throng of Gauls. Meanwhile, the Roman troops still encamped at the ruins of Veii fought against various Etruscan bands. Sensing easy spoils, the Etruscans made forays into Roman territory. Volunteers from the rest of Latium steadily swelled the Roman army at Veii. All that was needed was a capable leader. It turned out to be Camillus. With the consent of the Roman Senate, notified by a secret messenger, Camillus was nominated Dictator by order of the people.

According to Roman tradition, the Gauls attempted to infiltrate the Capitol by stealth. At night, a small party scaled the hill near the Temple of Carmentis, a goddess of birth. The climb was precarious but the party gained the summit and completely eluded the Roman sentinels. The Gauls did not even wake the guard dogs. Fortunately for the Romans, the Gauls next passed by the temple of Juno, the goddess of marriage and the wife of Jupiter. Here were kept a flock of sacred geese which put up such a racket that the Roman guard was finally roused. Led by Marcus Manilus, a veteran soldier, the guards confronted the infiltrating Gauls. Manilus faced two of the enemy, one of which wielded an axe. Manilus’ sword flashed and sliced through the axe-man’s right wrist. Blood spurted from the stump as the severed hand and axe hurled through the air. Manilus instantly confronted the second Gaul and smashed his shield into his adversary’s face. The Gaul tumbled backward, right over the parapet and down the cliff. The rest of the Gauls who had gained the parapet were dealt with likewise while a volley of javelins and stones dislodged the Gauls who still clung to the rocks. For his bravery, the surname Capitolinus was bestowed upon Manilus. The result of the fiasco was that the Romans kept stricter watch. The Gauls too tightened their security around the hill, for they had come to realize that messages were passing between Veii and Rome.

Despite their valiant defense of the Capitol, the Roman condition was far from desirable. The blockade continued for seven months and reduced them to famine. The Gauls equally suffered from malnutrition, along with severe outbreaks of malaria. Their dead piled up in such great numbers that efforts were no longer made to bury them. The corpses were simply piled into heaps and burnt.

Hunger so gnawed at the defenders of the Capitol that they gave up any hope of being relieved by Camillus. All that was left was to sue for a peace. A conference between the consular tribune Q. Sulpicious Longus and Brennus ended with the Romans agreeing to pay 1000 lbs of gold for the peaceful withdrawal of the Gauls. When it was time to weigh the gold, the Gauls produced heavier, false counter-weights. The Romans complained but to no avail, for Brennus threw his own sword on the scales and haughtily proclaimed “Woe to the vanquished!”

What happened next is shrouded in legend. Livy wrote that Camillus and his army now appeared on the scene. He at once ordered the Gauls to leave the gold and to march away from the city. When they refused to do so, a chaotic battle erupted as Romans and Gauls fought each other within the streets and alleys of the ruined city. The end was that the famished and disease-stricken Gauls were easily routed and driven out of the city. At the eighth milestone on the road to Gabii, the Gauls rallied but were again defeated by Camillus’ pursuing force. Plutarch mirrors Livy’s tale, except that he maintains that the skirmish in the city resulted in few Gallic casualties and that the Gauls retreated in good order until their defeat on the road to Gabii. In contrast to Livy and Plutarch, Polybius makes no mention of Roman heroics and tells us that the Gauls raised the siege because their own lands were threatened by an invasion of the Veneti, a pre-Celtic people of north-eastern Italy. Diodorus gives us yet another account in which the Gauls left Rome of their own free will after receiving the gold. Later they were defeated on two separate occasions, by Camillus at the town of Veascium and by the Caeretans in Sabine territory.

Most modern historians consider Camillus’ defeat of the Gauls to be little more than a fanciful revision by classical historians who were loath to admit Rome’s defeat at the hands of mere barbarians. But there is probably a bit of truth in the classical accounts. Perhaps the Gauls accepted the ransom because of pestilence and malnutrition within their own ranks and because of rumors of the Veneti invasion and a possible large gathering of fresh Roman forces in the countryside. On their way home the Gauls no doubt spread into smaller bands to ease their living off the land. Romans and other tribes might well have ambushed many of these bands and recovered part of the ransom gold.

Whatever the truth of the Gallic departure, the Romans ever after called their defeat at the Allia the dies ater (“black day”). The sack of their city left a deep impression on the Romans. Clearly the army needed improvement and the city defenses strengthening, to prevent future disasters at the hands of the Gauls. The first of these problems was addressed by Camillus. He began a series of army reforms that were further enhanced during the late fourth century wars against the Samnites, the tough mountain tribes of the south-central Apennines. The easily disordered phalanx was abandoned in favor of the tight, independent unit of the maniple. The maniple averaged 60 to 120-men strong, placed at intervals in a line. The maniples were much more elastic, both in attack and defense, than the old phalanx. Each maniple could independently fall back or advance, as the situation required, without messing up the whole battle line.

Volleys of javelins were used to prepare the way for combat with the short sword. The round shield was replaced by the more familiar Samnite scutum, a large semi-cylindrical four-cornered shield. Alongside the new army, Rome’s agger was raised and backed by a 12-foot thick and 24-foot high solid stone wall, circling the whole city for a distance of over five miles. Greek contractors may have built the wall, the labor being done by the Roman army and by Veientine captives.

The defeat at the River Allia discredited Rome in the eyes of her neighbors. The loyalty of Rome’s Latin allies began to waver while erstwhile enemies, the Aequi, Volsci and Etruscans, reopened old wars. What was won in over a hundred years was lost in a single battle. Fortunately for the Romans, for a long time after the battle on the Allia, the Gauls only raided into peninsular Italy sporadically. Instead, the Gauls concentrated on consolidating their hold on the north Italian plain, which, until the end of the Republican period, became known as Gallia Cisalpina.

3 thoughts on “Roman Meets Gaul

  1. Wonderful article related to Roman military history! I was especially interested in your description of the periodic Roman campaigns against Cilician and other pirate forces. I also have two questions related to the article. First, you mention that young Julius Caesar “arrested” the pirates who had originally captured him. Was the purpose of this arrest not only to take the pirates into custody but also to make the pirates (who had, prior to capture, represented a law unto themselves) subject to Roman criminal law and the associated penalties? Second, do you feel that the illustration that precedes the description of Pompey’s campaign against piracy is a fairly accurate portrayal of Roman v Pirate warfare? The illustration shows the legionaries equipped with swords, various piercing weapons, armor, shields, and well organized formations. By contrast, the pirates are depicted as having swords, but no armor and shields, and no organized formations. It seems that the pirates are dependent, to a great extent, upon hand-to-hand (and, in the case of the one pirate depicted, hand-and-foot) strategies. If this is accurate, could it also possibly explain Pompey’s very rapid victory over the pirates?

    Thanks again for the article. And I appreciate your attention.



    • Was this comment for Gnaeus Pompey’s World II.

      “When a pirate ship fell into the hands of Verres, governor of Sicily in 73–71 BC, members of the crew were re-employed by him for the various skills which they possessed and the pirate captain was allowed to ransom himself. Here indeed was a contrast to Caesar’s ruthless action, but Caesar after all had had a private score to settle with his captors.”

      “His work [Pompey] was carried out very methodically. The western Mediterranean was first combed of pirates, each of 13 naval squadrons having been assigned its separate operational zone. Pompey then proceeded eastward with 60 of his best ships to attack the main enemy strongholds. The western sea had been cleared in a mere 40 days. Within three months, the pirate bases of the east had also been stormed and occupied. The bulk of the enemy fleet had been destroyed in a major naval engagement, and those pirates who had sought refuge in inland fortresses with their families were besieged amid the mountains and captured. Prisoners numbered 20,000. Among many vessels captured were 90 warships complete with equipment.”


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