The Siege of Alesia

By Night_Raider


The Battle, or Siege, of Alesia was the last major engagement between Gallic and Roman forces during the Gallic Wars. Looking back, the battle at Alesia is said to have been a turning point in favor of the Romans as well, as in past battles (and most recently, the Battle of Gergovia) the Romans won key battles, but took heavy losses. The commander of the Roman forces was none other than Gaius Julius Caesar, a successful man, both politically and militarily, in Rome. Alongside Caesar stood the brilliant minds of Mark Antony, Titus Labienus, and Gaius Terbonius, all of which played important roles as cavalry commanders. The Gauls were led by a man named Vercingetorix, a man Caesar and likely all of Rome knew all too well.

Prior to the battle

Caesar had resided in Gaul since 58 BC, after the Senate of Rome appointed him governor towards the end of his Consulship, as was the custom, of both Cisalpine Gaul (the region of Gaul under Roman control that included the area between the Alps and the Apennines mountains, and the Adriatic Sea) and Transalpine Gaul. Over the years, Caesar won many successful battles and ultimately defeated several Gallic tribes, namely the Helvetii, Belgae, and the Nervii. During the winter of 54 and 53 BC, a Gallic tribe called the Ebjurones led by a man named Ambiorix, rebelled against Roman rule, and decimated the 14th Legion in an ambush. Caesar lost one-fourth of his total military forces as a result, and to make matters worse, the current political (among other things) situation in Rome made it impossible for Caesar to receive reinforcements. After this clever attack on the Romans, the Gauls realized that united, and only united, could they stand up against and possibly overthrow Roman rule and regain their independence. A group of prominent Gallic tribes gathered together and formed a council at Bibracte, one of the most important hillforts in all of Gaul. Modern archeologists believe Bibracte was located near modern Autun in Burgundy, France, and recently uncovered evidence supports this theory. The council was officially started by the Aedui tribe, who were ironically once Caesar loyal supporters and allies. Only the Remi and Lingones tribes stayed allied with Rome, probably out of fear of retribution. Vercingetorix, a man not soon forgotten, of the Avernii tribe was appointed commander-in-chief of the united Gallic forces.

Caesar was unaware that any such alliance was made against him, but there were signs. The Carnute tribe slaughtered all the Roman citizens in the Gallic city of Cenabum (modern Orléans). Many such attacks would follow as well. After Caesar could tolerate these attacks no more, he gathered an army and marched across the Alps and into central Gaul in record time. Such a feat surprised the Gauls. After the battle of Gergovia, Vercingetorix decided to regroup his army at the hillfort of Alesia.

The siege of Alesia

Being it was a hillfort, Alesia naturally possessed strong defensive features. Furthermore, it was surrounded by several river valleys. Given the placement of the fortifications, Caesar wisely decided not to go through with a frontal assault, as that would be suicidal. Instead, he decided a simple siege would do the trick. With the combined numbers of Alesia's garrison and the civilian population numbering over 180,000 men, women, and children, the siege would not last long.

To ensure that no one could get in or out of the fortifications, Caesar ordered the construction of a set of his own fortifications that would encircle Alesia, called a circumvallation. By the time it was finished, the circumvallation was over 18 km long with 9 foot high walls. The total construction time was relatively short, lasting only three weeks. Two four and a half meter wide ditches were dug behind the wall. Each ditch was about one and a half feet deep. The one nearest the wall was filled with water that had been diverted from a nearby river. This was sort of engineering feat was nothing new to Caesar, for this was the same man who diverted water from the Tiber River into the Circus Maximus for a mock sea battle. Caesar also dug several holes and planted sharpened stakes in an upright position in the holes. Any Gauls that did break through would inevitably impale themselves on the stakes.

Vercingetorix's forces did not stand idly by and watch as Caesar's army encircled them. Cavalry raids, meant to stop or at least slow the progress of the construction, were not at all uncommon. Caesar's Germanic auxiliary cavalry, however, had proved itself yet again, just as it had done so many times before in battle, by driving off Vercingetorix's own cavalry. Unfortunately for Caesar, a small detachment of Gallic cavalry did manage to break through an unfinished section. Caesar knew from what captured Gallic cavalrymen had told him, and his own instincts, that the Gauls would now send a massive relief force. Caesar then ordered the construction of a second set of fortifications, called the contravallation, which, upon its completion, would "sandwich" the Roman army between it and the circumvallation.

Conditions inside Alesia grew worse and worse by the day. It was a simple fact, too many people were trapped on a small plateau competing for too little food. The Mandubii tribe, the current owners of the Alesia hillfort, decided to attempt to expel the women and children in an attempt to conserve food for the warriors. Caesar was not that kind, however, and ordered that nothing was to be done for the women and children and that they would starve to death or surrender just like the men inside. With threats of surrender coming from his own men, Vercingetorix had trouble keeping the fighting spirit alive. Towards the end of September, in Vercingetorix's darkest hour of need, the Gallic relief force, commanded by Commius had finally arrived. They attacked Caesar's outer defensive wall, while Vercingetorix ordered a simultaneous attack on the inner defenses. The attacks were unsuccessful and the fighting was over by sundown. The next day, the Gauls attacked again, this time under the cover of darkness. This attack met with much more success, as Caesar was forced to abandon some sections of his fortifications. Had it not been for the quick thinking and swift cavalry tactics of Mark Antony and Gaius Trebonius, the outcome might have been staggeringly different.

The situation of the Roman army also appeared bleak. The men were near physical and mental exhaustion, and as the besiegers being besieged, they themselves were forced to ration food. On October 2, Vercassivellanus, Vercingetorix's cousin, launched a massive attack on a weak spot in the Roman fortifications, an area where natural obstacles prevented the construction of a continuos wall, with about 60,000 men. As before, Vercingetorix ordered a simultaneous attack on the inner defenses. By now, the weak area of the defenses was near collapse and Caesar ordered an all-or-nothing, almost suicidal attack. He led 13 cavalry cohorts (almost 6,000 men in total) and attacked the Gallic army from behind. The counter-offensive surprised both attacker and defender alike, and the Gauls soon panicked and ran. As Caesar would later describe in his book De Bello Gallico, only the sheer exhaustion of his troops saved the Gauls from utter annihilation.

Aftermath and Problems with Historical Accuracy

Alesia meant the end of organized resistance against the Romans; it also meant personal and political success in Rome for Caesar. The Alesia garrison was sold into slavery, including most of what remained of the relief force. Vercingetorix himself was taken prisoner and treated as royalty, as was the custom, for five years before he was taken to the Tullianum (or Mamertime Prison) and executed by strangulation.

The exact location of Alesia is unclear. Several sites have been brought up as a possibility, but only one closely matches the terrain the Caesar described later in his writing, that site being at Chaux-des-Crotenay at the gates of the Jura mountains. Excavations and research have revealed a Roman army camp that also closely described that which Caesar described as being his own.

The only records that currently exist of the battle are Roman, and are presumably bias. In Caesar's book, Caesar numbers the enemy relief force at over half a million men, but that was probably just an attempt to intensify the glory of his victory.