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Gallic Wars: The Battle of Alesia

James is an online writer from Birmingham who has a keen interest in ancient history. He enjoys sharing his research with his readers.

This article covers Julius Caesar, the Gallic Wars, and particularly the Battle of Alesia. This map shows the location of the Gallic tribes prior to Caesar's conquest. Incidentally, Roman-held territory is marked in yellow.

This article covers Julius Caesar, the Gallic Wars, and particularly the Battle of Alesia. This map shows the location of the Gallic tribes prior to Caesar's conquest. Incidentally, Roman-held territory is marked in yellow.

Julius Caesar and the Gallic Wars

In 59 BC, Julius Caesar was elected consul in Rome. He used his position and political connections to secure his appointment as the governor of Cisalpine and Transalpine Gaul and Illyricum at the conclusion of his term in office. He took up the governorship the following year and used the migration of the Helvetii and the trepidation this caused among Rome’s Gallic allies as a pretext to intervene militarily in Gaul.

While it does not seem that Caesar initially intended to conquer Gaul, his victory over the Helvetii may have provided him with the opportunity to contemplate doing so. Over the next five years, Caesar waged a number of successful, if sometimes close-run, campaigns in Gaul, forcing many tribes to submit to him, at least temporarily. Moreover, Caesar also launched campaigns across the Rhine and twice invaded Britain.

Despite his success, there was definite unrest in Gaul which began to manifest itself in late 54 BC. Due to a bad harvest, Caesar was forced to disperse his troops in winter quarters throughout much of north-east Gaul, requiring the various tribes to provide his troops with provisions. This led to serious resentment that soon burst into full and open rebellion.

Two legionary encampments were attacked during the winter of 54/53 BC. A legion of 10 cohorts with five additional cohorts, perhaps the cadre of a new legion under the command of Quintus Titurius Sabinus and Lucius Aurunculeius Cotta, was destroyed when the Romans were lured from their fortified camp, ambushed and annihilated. This was followed by an attack on a legion in winter camp under the command of Quintus Tullius Cicero (the brother of the famous orator Marcus Tullius Cicero).

Cicero wisely remained within his fortifications and, although his force was hard-pressed and suffered extraordinarily heavy losses, was able to hold out until he was relieved. Caesar spent the remainder of 53 BC raising additional forces, intimidating Gallic tribes and dealing with the Germans, both campaigning across the Rhine and fending off a major raid.

The Campaign and the Factions

At the beginning of 52 BC, the Gauls planned a coordinated effort that would become a general rebellion aimed at expelling the Romans. The revolt began early in the year with the massacre of Roman citizens living at Cenabum, city-state of the Carnuntes tribe. This signal inspired the Gauls, and a young, charismatic noble of the Arverni, Vercingetorix, to put together a coalition of tribes in order to field a significant army against the Romans and their allies.

The Gauls began by attacking the capital of the Boii, a tribe still allied with Rome, but Caesar, who had been away in Italy, returned and forced the Gauls to withdraw. Meanwhile, Caesar attacked several Gallic towns, no doubt in order to procure supplies at this difficult time of year. Vercingetorix realised that logistics were Caesar’s weak point and so the Gauls adopted a Fabian strategy, where they would avoid open battle with the Romans and fall back on and defend their fortified towns in an attempt to deny the Romans much needed supplies.

Meanwhile, Caesar continued to attack Gallic towns and attempted to force a confrontation. He moved into the territory of the Bituriges and attacked their major stronghold, Avaricium. Vercingetorix had tried to convince the Bituriges to abandon the town, but they were confident in its defences. Although he camped outside the town, he was unable to prevent the Romans from investing the town. Caesar attacked the town during a rainstorm, when it was least expected and was able to seize it, forcing Vercingetorix to retire.

Caesar took six legions and marched on the capital of the Arverni at Gergovia. This town was clearly important to Vercingetorix and he had every intention of trying to defend it. When Caesar reached the town, which was located in very hilly terrain, he seized a hill and established a fortified camp there. He rapidly seized another hill and established a small camp there too. He then proceeded to connect the two with a pair of parallel ditches.

Caesar noticed a small hill that provided access to the town and that was virtually undefended. He ordered some of his troops to provide a distraction, while he launched an attack on the hill which he took with relative ease. The troops, however, continued on to the town walls, whether at Caesar’s direction or, as he would have it, they simply got carried away by their success. Upon reaching the walls, they met stiff resistance and were driven off with heavy losses, particularly amongst the centurions. At that point, Caesar was forced to raise the siege and withdraw from Gergovia.

The defeat at Gergovia was a serious blow to Caesar and a benefit to Vercingetorix. The defeat caused some of Caesar’s oldest Gallic allies to defect to the enemy. Vercingetorix set about recruiting additional troops for the rebellion and, using a large cavalry force, began interdicting Roman efforts to gather supplies. Caesar was not idle.

To make up for the losses caused by the defections, especially in his cavalry, he recruited German cavalry and light infantry to support them. It became clear to Vercingetorix that his forces could not stand up to Caesar’s in open battle, particularly with the addition of the German cavalry, and decided to fall back on the fortified town of Alesia, hoping to repeat the defeat of the Romans at Gergovia. Caesar followed him and prepared to invest in the town.

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This is a modern reconstruction of the Alesia investment fortifications.

This is a modern reconstruction of the Alesia investment fortifications.


Vercingetorix and his army built a fortified camp adjacent to Alesia defended by a ditch and rampart 6 feet high. Caesar concluded that Alesia and the Gallic camp were far too strong to be assaulted and so decided instead to surround and blockade the town. He started by constructing seven fortified camps supported by 23 redoubts to defend key positions.

While these fortifications were being constructed, Vercingetorix sent out his cavalry to interfere with the Romans. A cavalry battle ensued in which the Gauls were badly mauled by Caesar’s cavalry, especially the Germans. Vercingetorix then decided to have his cavalry attempt a breakout during the night. The Gallic horsemen slipped out through gaps in the Roman lines and went back to their communities to raise a new army to relieve the siege.

With the escape of the Gallic cavalry and the likely appearance of a relief army, Caesar decided to augment his siege works. First, he constructed a 20-foot ditch with perpendicular sides to prevent the Gauls in Alesia from interfering with his construction of more complete fortifications. Behind this ditch, two additional ditches were dug, with the inner one filled up with water to form a moat. Behind these was a 12-foot high rampart, erected from dirt excavated from the ditches. This was surmounted with a palisade and protected by sharpened stakes. To further reinforce the rampart, towers were placed along its length at regular intervals. The length of these works was nearly 10 miles.

During the construction of the fortifications, Vercingetorix made a number of substantial and coordinated sorties from the town, which interfered with construction and made it difficult for Caesar to send out foragers. He therefore added three lines of traps to make any enemy attack more difficult.

The first consisted of five rows of sharpened tree trunks and stout branches set in trenches, in front of them were 3-feet-deep pits arranged in the fashion of a chessboard, with sharpened stakes set inside, and in front, iron hooks set in wooden blocks were scattered about.

In order to defend against the relief army, a similar set of fortifications 17 miles in length were built facing outwards with plenty of room in between for Caesar to move his troops. Caesar also had his men collect a one-month reserve of food and fodder. The Gauls within Alesia recognised that supplies would become short so they sent out all those who were unable to fight. The noncombatants went to the Roman lines but were turned away by Caesar and so were left to starve in a no man’s land.

This map highlights the fortifications constructed by Julius Caesar according to archaelogical evidence.

This map highlights the fortifications constructed by Julius Caesar according to archaelogical evidence.

The Battle of Alesia Reenacted in Film

The Battle of Alesia

The battle began as the relief force arrived and, after having camped within a mile of the Roman lines, sent out their cavalry into a 3 mile wide plain. The Gallic horse had archers and light infantry interspersed, while the main body of infantry formed up to watch their cavalry who were the elite of the army. When the Gauls within Alesia saw the cavalry formed for battle, they came out of the town and started to fill in the Roman trenches with fascines in preparation for a sortie.

Caesar responded by manning the ramparts with all of his infantry, making sure that each man knew his post, and sending out his Gallic allied and German horse to meet the enemy cavalry. The cavalry action was fiercely contested, the Gallic horse benefiting from the support of the infantry in their midst, something the Romans had not expected.

The fighting lasted from noon until sunset, but eventually, the Romans had the better of it when Caesar massed his German cavalry at a single point; the result was successfully breaking through the Gallic cavalry. The latter fled leaving their infantry supports to be slaughtered and were pursued back to their camp. The Gauls within the siege works despaired and retired back to Alesia.

The Gauls of the relief force spent the following day preparing the materials needed for a major assault, including ladders, grappling hooks and fascines. At midnight, they quietly advanced and, once near the Roman siege works, gave a shout to let the besieged know that they were beginning the assault. As a result, Vercingetorix led out his forces to attack the Romans at the same time, so that they (the Romans) would be engaged to front and rear at the same time.

Although the Gauls were able to cause a number of casualties by hurling javelins, slinging stones and other missiles, the obstacles set up by the Romans before their ramparts made it extremely difficult and caused heavy losses. The Gauls were unable to penetrate the Roman lines and, fearing a counter-attack, retreated in good measure.

The Gauls held a council of war and decided to use the main army to threaten the siege works while a force of 60,000 picked men attacked a Roman camp on the north side of the town. The fort was defended by two legions, but due to the nature of the terrain, it lay outside of the lines of circumvallation. Meanwhile, Vercingetorix would again lead an attack so the Romans would be forced to defend both the inner and outer defences against simultaneous assaults.

The Gallic force of warriors marched through the night and rested until noon at which point they attacked. At the same time Vercingetorix attacked the inward facing fortifications so that the Romans were hard pressed at several places. Caesar noticed that the 60,000 Gauls were having some success against the isolated fort and so he sent his most trusted lieutenant, Titus Atius Labienus, to its relief with six cohorts. He ordered Labienus to defend the fort but if it appeared he could no longer defend it, he should instead counter attack. In the meantime, Vercingetorix’s troops had breached a steep section of the inner wall where the fortifications were not as complete.

Caesar sent reinforcements to this position, eventually repulsing the Gauls when he personally led some troops to the breach. By this point, the situation had become desperate and Labienus was preparing for a last-ditch counter attack. Caesar rushed to aid the counter attack leading a mere four cohorts, but he also ordered his cavalry to sally out and assault the Gallic warriors from behind.

Although the Gauls put up a fight, the appearance of cavalry behind them was too much and they were routed. The Roman cavalry was able to cause tremendous casualties amongst the routing Gauls. The besieged Gauls were totally dismayed by this turn of events and retired into Alesia.

This painting depicts Vercingetorix surrendering to Julius Caesar in the aftermath of the battle. It should be noted that in reality Caesar would have been dressed as a soldier rather than a politician as shown here.

This painting depicts Vercingetorix surrendering to Julius Caesar in the aftermath of the battle. It should be noted that in reality Caesar would have been dressed as a soldier rather than a politician as shown here.

Aftermath of Alesia

With the rout of the relief army, the Gauls within Alesia were forced to surrender. Vercingetorix was handed over to Caesar. Some of the Gauls were used to help gain the loyalty of their tribes but many were distributed to the troops as booty and ended up as slaves.

The victory at Alesia effectively broke Gallic resistance, although Caesar would spend the next two years consolidating his position. Vercingetorix would remain a prisoner for some six years until, after having been paraded in Rome during Caesar’s great triumph, he was publicly strangled.

Reenactment and Explanation of the Battle of Alesia

Sources and Further Reading

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


Mark on October 26, 2019:

To be fair, it’s not a great outlook to judge people of the past by today’s morals. Let’s not overlook the fact Vercingetorix left all the women, children and elderly of the village starve to death to ensure his soldiers had enough to eat. These were his people. Also we wouldn’t even know Vercingetorix’s name if not for Julius as all the accounts of this battle were from Julius’ journals. Where he definitely shed the Gallic king in a favourable light. If only people today were so kind.

James Kenny (author) from Birmingham, England on November 13, 2012:

I totally agree Letitia, it baffles me as to how a man like Caesar can be idolised, and yet Vercingetorix is often forgotten. Caesar was a`warmongering imperialist, trying to live up to Alexander. Vercingetorix in my eyes was a hero willing to stand up to the mightiest army in the world at the time. He very nearly succeeded in defeating it too.

LetitiaFT from Paris via California on November 13, 2012:

What an excellent write-up of events. I have visited both sites, Alesia, which saw Vercingetorix's defeat by Ceasar, and the Gergovie plateau, which saw his victory against him. Fortunately, I saw them in that order, which has left me with the feeling Vercingetorix was victorious in the end, despite knowing the contrary is true. Certainly he remains a hero in my eyes; how many men could boast any victory at all against the conquering Romans? To have Vercingetorix strangled publicly in Rome after carting him around for years in a cage was no show of Ceasar's military might, but of his weak moral character.

James Kenny (author) from Birmingham, England on November 13, 2012:

Hi Thomas, the Romans regarded the Gauls as little more than animals, which is why they paraded them before great crowds. In reality though, it was the Romans who were the barbarians. Caesar killed millions of Gauls and wiped out something like 40 independent tribes. Put in the context of the 20th century, he belongs in the same league as Hitler, Stalin, Mao and Pol Pot etc. Yet he is idolised! Bizarre.

James Kenny (author) from Birmingham, England on November 13, 2012:

Thanks CM, really glad you liked it. Appreciate you dropping by.

CMHypno from Other Side of the Sun on November 13, 2012:

Interesting hub on the Siege of Alesia, JKenny. Roman history is not something I have really studied extensively, so thanks for the great information,

Thomas Swan from New Zealand on November 13, 2012:

I read a historical novel about the Roman Empire called Lustrum (Robert Harris) where the Roman generals would parade their captured counterparts during their victory celebrations, and ultimately, execute them publicly. I see that happened to Vercingetorix. I find the lack of respect they showed their adversaries to be quite shocking, and quite at odds with the popular image of Romans as having some kind of `military honour'.

James Kenny (author) from Birmingham, England on November 13, 2012:

I know its amazing. I actually wrote a series of hubs about Julius Caesar, but barely mentioned Alesia. So it was interesting to research and write about it in greater detail. Thanks for stopping by, appreciate it.

David Hunt from Cedar Rapids, Iowa on November 13, 2012:

Wow. So Caesar basically built a fort around the town he was laying siege to. Great article, JKenny, about a topic I only know in passing.

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