The Siege and Battle of Alesia (or Julius Caesar Conquers Gaul)

I have made it no secret that I am a HUGE fan of Julius Caesar. And why shouldn’t I be? He was only one of history’s greatest soldiers, generals and politicians. However, it was in Gaul that Caesar truly made his mark. Here he was Consul in the First Triumvirate as well as Governor.


Caesar was in debt for power he had acquired. In the ancient world power came at a price. In order to conquer as much as Caesar did, a leader needed to pay his soldiers well. This way the soldiers also remained loyal only to that leader, and in this case the leader was Caesar.

Where could somebody get enough money, and ager publicus, to pay off one’s debt PLUS keep all the soldiers happy? The answer was easy…Gaul (present day France, Luxembourg, Belgium, most of Switzerland, the alpine region of Northern Italy, including parts of the Netherlands and Germany on the west bank of the Rhine). At the time Gaul was part of the Roman frontier. The land was comprised of various chieftains, princes, kings, etc. but it all still fell under the Roman umbrella.

Gaul on the eve of Rome’s conquering

Caesar, and the legions under his command, had been in Gaul since 58 BC. The Roman force stormed about Gaul taking over the lands, and sending the conquered warriors east to become part of the legions around the eastern portion of the Mediterranean. This was a common practice to send those newly conscripted soldiers to the opposite ends of the Empire so they would never be stationed in their homeland, thus never fighting against their own people. Seeing as how this was already Caesar’s proclaimed turf from the Triumvirate, it was primed for his taking.

The only thing that stood in Caesar’s way of full control over Gaul Alise-Sainte-Reine_statue_Vercingetorix_par_Millet_2was Vercingetorix and those Gallic tribes in Getorix’s command. Obviously this did not make Caesar, nor his legions, happy. Battle upon battle occurred and Caesar’s Fourteenth Legion was actually destroyed in 53 BC. But, it did come with a price. Vercingetorix and his Gauls knew they could not keep this up and compete with any Roman army in a head-to-head battle, so they would attack and fall deeper into the country. This drew Caesar deeper into the Gallic countryside and extended the Roman supply lines for mile-upon-Roman-mile.

Realizing that this style of fighting would never do, Caesar forced Getorix to make a choice for one last stand off, one last battle. Due to the retreat of Getorix to the hilltop fortification of Alesia, Caesar knew he had to use the power and ingenuity of Rome to his advantage. Caesar marched his legions into camp at the base of the hill and set his troops to work.


The year was 52 BC. The scene was set for a final standoff. Caesar and all that Rome stood for against the last of “lowly” people of the West. It was fame, glory, and money against a people that were trying not to be annihilated. How was this going to end? One of Caesar’s, and history’s, greatest military accomplishments was about to happen. first glance it looks like any other siege of a stronghold. Defenders atop a mountain while the base is surrounded. This is true. There is nothing unique about a siege line, except Caesar never did anything basic. The Roman siege line was 18 kilometers (11.1847 miles) long by 4 meters (13.1234 feet) high of fortification . It also was designed and completed in only 3 weeks.

You may be thinking, “Wow, that’s impressive.” and you would be correct. But Caesar did not stop there. His men then made an angled slope down from the ramparts to make it harder for attackers to climb. The Roman engineers also added two four-and-a-half meter (14.7638 feet) wide ditches which were also four-and-a-half meter (14.7638 feet) deep. The ditch closest to the mountaintop fortification was filled with water. It turns out that horses, which the Gauls typically fought upon, do not like jumping into water.

pages.uoregon.edukliomapsrralesia_defenses2Julius Caesar puts it best in his Commentaries on the war in Gaul, Book 7, Chapters 63-90 on what else was added: “In front of these, pits were dug, arranged in diagonal rows to form quincunxes. They were one meter deep and tapered gradually towards the bottom. Smooth stakes as thick as a man’s thigh, with sharpened ends and hardened in the fire, were set into these pits in such a way that they projected no more than four inches above the ground. To keep them firmly in position, earth was thrown into the bottom of the pits and trodden down to a depth of one foot, the rest of the space being covered with twigs and brush wood to conceal the trap. The pits were constructed in groups; each group had eight rows, three feet apart. The soldiers called them ‘lilies’ because of their resemblance to that flower. In front of these we had another device. Wood blocks a foot long were sunk completely into the ground, with iron hooks fixed in them, and scattered thickly all over the area. These the soldiers called ‘goads’.”

If you are not impressed yet, just wait. About 2 weeks into the construction, a Gallic cavalry unit managed to break through a weak side of the siege line. Caesar was obviously not pleased with this. In order to keep the siege going the Romans needed their own rear to be protected. How did they do it? They just built another siege line facing the other direction. The second line was identical to the first in design and extended for 21 kilometers (13.0488 feet). Siege line 2.0 was even completed in less time than the first.

The trap was set. The Romans were completely surrounded by safety. The 80,000 Gauls upon the hill, both soldiers and general population, were now suffering mightily. There was nothing left for Vercingetorix and his people to do. Either die on the hill or fight and possibly die trying to break the siege line. An orchestrated attack of the Gauls on the inside was combined with about 60,000 soldiers from other Gallic tribes on the outer ring.

Mass confusion abounded from everyone. The Gauls started to break the Roman lines, but it was then that the Romans fought even harder to protect their mighty Caesar. When all was said and done, Vercingetorix saw the outcome from atop the hill. The Gauls were finished. Getorix then came down and surrendered himself for execution and his people for slavery as long as Caesar would let his people live. Caesar let both Vercingetorix and the Gauls live. Getorix accompanied Caesar back to Rome, in chains. The Gauls were either made slaves, soldiers or tax-paying subjects.

Vercingetorix surrenders to Julius Caesar at Alesia
Vercingetorix surrenders to Julius Caesar at Alesia

The siege was over and Gaul would become part of the Roman Empire for the next 500 years. Caesar would gain acclaim and popularity across the land. Even more importantly, Caesar gained a life-long loyalty from all his men. It would not be long before Caesar returned to Rome for his triumph, with the wild-haired Vercingetorix in chains as his prize, and things would then get interesting.

After this victory the Roman Empire would never be the same. If Caesar was not victorious at Alesia, or any of his other battles for that matter, the world we live in today would not be the same. If you enjoy Europe, the next time you are journeying around make sure to tip your cap to Julius Caesar for what he helped create.

Have a great trip and remember to Rome…If you want to!

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