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The Battle of Alesia was fought in September of 52 BC during the Gallic Wars, when Julius Caesar's 75,000-strong Roman army laid siege to the fortified Mandubii settlement of Alesia, held by 80,000 Gauls under Vercingetorix. The Romans defeated a 248,000-strong Gallic relief force before forcing Vercingetorix to surrender, ending Gallic resistance to the Roman conquest of Gaul.


Following the Battle of Gergovia, several more Gallic tribes joined Vercingetorix's anti-Roman coalition, threatening to cut off the Roman armies in Gaul from Transalpine GaulJulius Caesar and his legate Titus Labienus joined forces at Agedincum before moving through the Sequani territory in the east to secure a route of retreat into Transalpine Gaul. He defeated Vercingetorix's attempt to attack his ten legions as they tried to cross the Vingeanne River, easily repelling the 80,000 Gauls. This minor defeat led to Vercingetorix withdrawing to the fortified Mandubii capital of Alesia, hoping to lure Caesar into a siege battle which would, like Gergovia, be to the Gauls' advantage. Caesar and his 11 legions (50,000 legionaries) and 15,000 auxiliaries marched on Alesia, where Vercingetorix and his 80,000 warriors waited on the high ground for his allies to arrive.


Starved Gauls

Dead Gallic civilians at Alesia.

Caesar had learned his lesson from Gergovia, fully surrounding and besieging the city and building a 16-kilometer wall of trenches, palisades, and towers to cut off any Gallic escape. Vercingetorix sent his cavalry to disrupt these works, but the legionaries held off these attacks with the help of Germanic mercenaries. The Gallic cavalry were massacred as they funneled through the city's narrow gates in retreat, and, at night, Vercingetorix sent the remnants of his cavalry to sneak past the Roman lines to request reinforcements. Upon completing the first wall, Caesar learned that the messengers had been sent, so he then built a moated 21-kilometer wall to hold off any Gallic reinforcements. Caesar sent huge foraging parties to collect a month's worth of supplies, leading to the Gauls now facing a well-dug-in enemy. It was only a matter of time before the Gallic defenders and civilians would be starved out, so Vercingetorix decided to expel all of the city's non-warriors. Caesar refused to let the civilians pass, and neither side gave them food or water as they starved between the city walls and siege lines.

Soon after, Vercingetorix's Gallic allies under Vercingetorix' cousin Vercassivellaunos arrived to lift the siege, bringing 248,000 warriors with him. The Romans were now significantly outnumbered by at least two-to-one, and the Gauls filled in the first Roman trench before probing the Roman army. Caesar sent out his own Germanic cavalry to skirmish with the Gauls, and the Gauls in the town prepared to sally forth. However, the Germans outmaneuvered and flanked their Gallic rivals, forcing them back across the trench and into the Gallic camp. Vercingetorix decided to hold off his attack, and the Gallic reinforcements built siege ladders and attacked the Romans that night. Mark Antony held the troubled seciton of the wall, pulling troops from other sections to reinforce his position. Vercingetorix was delayed with filling the Roman trench as his allies were repulsed, and Vercingetorix was forced to withdraw when Antony turned his attention to the garrison. Vercassivellaunos discovered some strategic high ground and attacked the entire length of the outside wall below the high ground, and Vercingetorix attacked the length of the interior Roman forces.

In the toughest fighting yet, Caesar dashed from cohort to cohort and led reserve cohorts to faltering defenses while rallying his men. Vercassivellaunus piled earthworks against the walls in order to mount them, and he used hooks and siege engines to pull down the walls. The Romans fought a desperate battle to prevent themselves from being wiped out, and Caesar later appeared at the top of the hill with his Germanic auxiliaries and attacked the Gauls from the rear. The Gauls who had pushed through the breach were decimated, and the rest of the Gallic reinforcements fled in terror. With this threat thus neutralized, the Romans focused on dealing with Vercingetorix, who was forced back into the city. Vercingetorix was forced to surrender his surviving warriors, with 250,000 of the Gauls being killed and 40,000 captured; the entire besieged army was killed or enslaved, and both Vercingetorix and his cousin were taken alive.