Caesar's victory at the Battle of Alesia, where Roman military engineering prowess enabled him to defeat a vast Gallic army rushing to the aid of their leader Vercingetorix, secured Roman rule in Gaul. Although, with all his fortifications, Caesar had to put up a tough fight.
Data from the Battle of Alesia
- Who: Gaius Julius Caesar (100-44 BC), with an army of 45,000 men, besieged an army of some 70,000 Gauls under the command of Vercingetorix of the Arverni (d. 46 BC) and faced a force reportedly numbering 250,000 warriors .
- How: Caesar used Roman expertise in siege operations, building lines of siege fortifications leading in and out, and Roman discipline to defeat threats from besieged and relief forces.
- Where: Alesia, about 50 km northwest of present-day Dijon, France.
- When: Late September/early October 52 BC
- Why: Caesar was trying to crush, once and for all, Vercingetorix's threat to Roman rule.
- Result: The battle was the last effort of the Gauls against Caesar. The defeat of the charismatic Vercingetorix ended The ability of the Gauls to resist the Romans.
Backgroundofthebattleofalesia
In 59 BC Gaius Julius Caesar was elected consul in Rome. When he finished his consulship, he used his position and his political contacts to secure his appointment as governor of Cisalpine and Transalpine Gaul and of Illyria. He held the post of governor the following year and used the emigration of the Helvetii, and the unease this caused among Rome's Gallic allies, as a pretext to intervene militarily in Gaul . Although it does not seem that Caesar's initial intention was to conquer Gaul, his victory over the Helvetii may have given him the opportunity to consider this option. Over the next five years, Caesar successfully led a series of campaigns into Gaul, albeit sometimes narrowly, forcing many tribes to submit to him, at least temporarily. Furthermore, Caesar also undertook campaigns across the Rhine, and invaded England twice .
Despite his success, there was a clear malaise in Gaul, which began to manifest itself at the end of 54 BC. Because of the bad harvest. Caesar was forced to disperse his soldiers into winter quarters throughout northeastern Callia, demanding provisions from the various tribes . This caused strong resentment that erupted into open rebellion. During the winter of 54/53 BC, a legion of 10 cohorts, with five additional cohorts, under the command of Quintus Titurius Sabinus and Lucius Arunculeius Cota, was destroyed when the Romans were lured out of their fortified camp, ambushed, and annihilated. This was followed by an attack on a legion in their winter camp, which was under the command of Quintus Tullius Cicero (the brother of the famous orator Marcus Tullius Cicero). Cicero remained within his fortifications and, although his forces were hard pressed and suffered heavy losses, he was able to hold out until he was relieved. Caesar spent the rest of 53 B.C. recruiting additional forces, intimidating the Gallic tribes, and dealing with the Germans, both in campaigns across the Rhine and repelling a major raid.
Thecampaignandthearmies
Early in 52 BC, the Gauls planned a general rebellion aimed at driving out the Romans . The revolt began at the beginning of the year with the massacre of Roman citizens living in Cenabum, a city-state of the Camuto tribe. This signal inspired the Gauls, and a charismatic young Arverni nobleman, Vercingetorix, to assemble a coalition of tribes and field a significant army. The Gauls began by attacking the capital of the Boii, a tribe allied with Rome, but Caesar, who was in Italy, returned and forced the Gauls to withdraw. Meanwhile, Caesar attacked several Gallic towns, in order to procure provisions. Vercingetorix realized that logistics was Caesar's weak point, and so the Gauls adopted a Fabian strategy, in which they would avoid open combat against the Romans and would withdraw and defend their own fortified towns, in an attempt to deprive the Romans of much-needed provisions .
Meanwhile, Caesar continued to attack Gallic towns and tried to force a confrontation. He entered the territory of the Bituriges and attacked their main fortress, Avaricium. Vercingetorix attempted to convince the Bituriges to leave the town, but they were confident of their defences. Although he camped outside the town, he was unable to prevent the Romans from besieging it. Caesar attacked the town in torrential rain, when least expected, forcing Vercingetorix to retreat. Caesar took six legions and marched against the capital of the Arverni:Gergovia.
Gergovia
This town was very important to Vercingetorix, who intended to defend it. When Caesar reached the town, which was situated on very broken ground, he occupied a hill and established a fortified camp there. He quickly took another hill, established a small camp there, and connected the two with a pair of parallel ditches. César observed a small hill that gave access to the population and that was practically defenseless. He ordered some of his soldiers to start a diversionary maneuver and launched an attack on the hill, which he took with relative ease. . The soldiers, however, continued their advance to the town walls, either under Caesar's orders or, as he relates, simply excited by their success; they met strong resistance there and were repulsed with heavy losses, especially among the centurions. At this point Caesar was forced to lift the siege and withdraw from Gergovia.
Gergovia's defeat was a heavy blow to Caesar and an advantage to Vercingetorix. The defeat caused some of Caesar's oldest Gallic allies to defect to the enemy .
Retreat to alesia
Vercingetorix began to recruit additional troops for the rebellion and, using a large cavalry force, began to intercept Roman efforts to gather supplies. Caesar, to compensate for the losses caused by the defections, especially in his own cavalry, recruited German cavalry and light infantry to back it up. Vercingetorix realized that his forces could not meet Caesar's in the open, and he decided to withdraw to the fortified city of Alesia, hoping to repeat the defeat of the Romans in Gergovia . Caesar followed him and prepared to besiege the city.
Layouts
Vercingetorix and his army built a fortified camp adjacent to Alesia. defended by a moat and an embankment 1.8 m high. Caesar concluded that Alesia and the Gallic camp were too strong to be assaulted, and decided instead to surround and blockade the city . He began by building seven fortified camps supported by 23 redoubts to defend key positions. While these fortifications were being built, Vercingetorix sent his cavalry to hamper the Romans. A cavalry battle ensued, in which the Gauls were severely beaten by Caesar's cavalry, especially the Germans . Vercingetorix then decided that his cavalry would attempt an escape during the night. Gallic horsemen slipped through the gaps in the Roman ranks and returned to their communities to raise a new army to succor the besieged.
With the flight of the Gallic cavalry and the probable appearance of a relief army, Caesar decided to increase his siege constructions.
First, he built a 6 m moat, with perpendicular sides, to prevent the Gauls from Alesia from hindering the construction of more complete fortifications. Behind this pit, two
additional moats, and the interior was filled with water. After these, a 3.6 m high embankment was erected with the earth extracted from the pits. This was crowned with a palisade and protected by sharp stakes. To further strengthen the embankment, regularly spaced towers were arranged along it. The length of these constructions was almost 16 km.
Vercingetorix, during the construction of the fortifications, made a series of important and coordinated sorties out of the city, which interfered with the construction and made it difficult for Caesar to send supply parties . This one, he added three lines of traps. The first consisted of five rows of tree trunks and strong sharp branches, placed in ditches; In front of these there were holes 90 cm deep arranged in the form of a chessboard, with sharp stakes inside; and, ahead, iron hooks fixed to wooden blocks were scattered.
To defend against the relief army, a similar set of fortifications, 28 km long, were built facing outwards, with enough space in between for Caesar to move troops from him. The Gauls inside Alesia recognized that supplies would be insufficient, so they sent all those unable to fight out of the city. The non-combatants made their way to the Roman lines, but were repulsed by Caesar, and thus were left waiting to starve in no man's land.
The Battle of Alesia
The Battle of Alesia began when the relief forces arrived and, having camped 1.5 km from the Roman lines, sent their cavalry into a 5 km wide plain. The Gallic horsemen were interspersed with archers and light infantry, while the main body of infantry formed up to watch over their cavalry, who were the elite of the army.
Engagement outside fortifications
When the Gauls of Alesia saw the cavalry arrayed for battle, they marched out of the city and filled the Roman ditches with sashes, in preparation for a sortie. Caesar responded by manning the ramparts with all his infantry, making sure all the men knew where he was stationed, and sending his allied Gallic and Germanic horsemen to meet the enemy cavalry. The action of the cavalry was hotly contested, as the Gallic horsemen benefited from the support of the infantry, something that the Romans did not expect, but finally the Romans had the better part, when Caesar concentrated his German cavalry in a single point and disbanded to the Gallic cavalry. The latter fled, leaving his supporting infantry to be massacred. The Gauls inside the siege fortifications gave up hope and retreated back to Alesia.
Assaultontheromanfortification
The Gauls of the relief force spent the next day preparing the materials needed for a major assault, including ladders, assault hooks, and cummerbunds. At midnight, they advanced silently, and when they came close to the Roman siege fortifications, they gave a call to signal to the besieged that they were going to start the assault. Vercingetorix went out with his forces to attack the Romans at the same time, so that they were fought from the front and from behind . Although the Gauls were able to cause a number of casualties by throwing javelins, slingshots and other projectiles, the obstacles placed by the Romans in front of their ramparts caused heavy losses. The Gauls, unable to continue, withdrew.
Endofthebattleofalesia
The Gauls held a council of war and decided to use the main army to threaten the siege fortifications, while a force of 60,000 picked men attacked the Roman camp in the northern part of the city. This fort was defended by two legions but, due to the nature of the terrain, it was outside the bypass lines. Meanwhile, Vercingetorix would again lead an attack so that the Romans would be forced to defend both the inner and outer fortifications against simultaneous attacks . The force of Gallic warriors made a night march and rested until noon, at which time they attacked. At the same time, Vercingetorix attacked the inner fortifications to embarrass the Romans in several places. Caesar saw that the 60,000 Gauls were having some success against the isolated fort, so he sent his most trusted lieutenant, Titus Atius Labienus, to succor him with six cohorts . He ordered Labienus to defend the fort, though he was to counterattack in case he was unable to defend it. Meanwhile, Vercingetorix's soldiers had breached a steep section of the inner wall, where the fortifications were not so complete.
Caesar sent reinforcements to this position, finally repulsing the Gauls when he personally led some soldiers into the breach. The situation had become desperate, and Labienus was preparing for a final counterattack. Caesar quickly went to reinforce the counterattack at the head of just four cohorts; he also ordered his cavalry to make a sortie and attack the Gallic warriors from behind. . Although the Gauls fought vigorously, the appearance of the cavalry from behind was too much and they were defeated. The Roman cavalry was able to inflict heavy casualties on the fleeing Gauls. The besieged Gauls were dismayed and retreated into Alesia.
Aftermath
With the relief army dispersed, the Gauls inside Alesia were forced to surrender. Vercingetorix was handed over to Caesar . Some of the Gauls were used to gain the loyalty of their tribes; however, many were distributed among the troops as booty and ended up as slaves. The victory at the Battle of Alesia broke the Gallic resistance, although Caesar would spend the next two years consolidating his position . Vercingetorix would remain a prisoner for some six years until, after being paraded through Rome during Caesar's great triumph, he was publicly strangled.