Battle of Alesia (52 BC)

In 60 b.c. Julius Caesar entered into a political alliance with the two most powerful men in Rome, Crassus and Pompey, forming the "Triumvirate." The three ruled the Roman Republic together while at the same time each tried to maneuver himself into a position of dominance. In order to do this, wealth and political influence were necessary, but military experience and army support were vital. Crassus had experience, making himself famous by crushing the Spartacus slave uprising. He then assumed the governorship of Syria so he could gain more laurels and wealth in a war against the Parthians. He died trying. Caesar took the position of governor of Cisalpine and Transalpine Gaul (northern Italy and southern France), where he hoped to gain the military and financial power he needed. Caesar began fighting almost immediately: between 58 to 53 b.c. he campaigned against tribes of Gauls (the Roman term for the population of northwestern Europe/France; they called themselves Celts) throughout modern France and across the Rhine into Germany. His string of victories brought leadership experience while he enriched himself with untold pillage. He established a strong Roman presence in the region of modern Belgium by the spring of 53, when he defeated the Nervii and Belgae tribes. Caesar then left for northern Italy to reinforce his political contacts.

Those victories did not awe many Gauls, but they began to realize that as long as they practiced their traditional internecine warfare they would never defeat Rome's power. In 53 b.c. the tribes finally rallied around a single leader, Vercingetorix, chieftain of the Arverni. Forging a Gallic coalition was a virtually impossible feat, and it is a tribute to Vercingetorix's personality and leadership characteristics. Dozens of tribes and literally hundreds of thousands of people swore allegiance to him, including many Caesar had thought were securely loyal. Vercingetorix organized and trained the Gallic warriors to a level they had never before attained, then launched his first offensive against Cenabum (modern Orleans) in late 53 b.c. After capturing the town, he slaughtered the entire Roman population and took control of Rome's major grain cache in Gaul. Hearing of these events, Caesar realized that the entire Roman position above the Alps was in danger. In January 52 he returned from Italy to his headquarters in Provence.

From Provence Caesar marched his troops north to Belgica (modern Belgium), joined his legions there, then countermarched to attack Cenabum on the Loire River. He recaptured the city (the source of the current rebellion), then divided his army, marching southward while sending a sizable force under Labienus to secure northern Gaul. All of this marching and fighting took place in the late winter months, a factor Vercingetorix used to his advantage. He commanded the destruction of every bit of food and forage that was available along Caesar's assumed line of march, out to a distance of a day's march. This was a brilliant strategy, and Caesar soon felt its effects. To make matters worse, Caesar's primary ally in Gaul, the Aedui (on whom he had depended for food), began showing signs of disloyalty. Some leaders convinced the tribe that the Romans had been ravaging the countryside and killing Aedui hostages. Caesar intercepted a column of 10,000 Aedui who had been marching to reinforce the Romans before being persuaded to join Vercingetorix. When Caesar produced the hostages that had supposedly been killed, the rabble-rousers fled and the remainder of the force joined with the Romans.

Caesar next besieged the town of Avaricum (modern Bourges) in March 52, capturing the town before Vercingetorix could arrive to relieve it. With refilled Roman supply wagons, he next attacked and captured Gergovia, Vercingetorix's capital. Although he laid siege in April and May he could not live off the land, for the countryside surrounding the town had been stripped of supplies, which were now stockpiled inside the fortress. Desperate to take the town before a relief force could arrive, Caesar ordered an assault that cost him more than 700 casualties, including almost fifty centurions. The defeat and the lack of supplies forced him to retreat. Marching north he joined Labienus, who had just captured Lutetia (Paris); together they aimed toward Provence. Vercingetorix was determined that they would not reach it.

Accurately predicting Caesar's intent, Vercingetorix withdrew his army of 80,000 infantry and 15,000 cavalry into the fortress town of Alesia (Alise-Ste.-Reine), near the source of the Seine River. He also sent a cavalry force north to harass and delay the Romans. They engaged Caesar's Germanic auxiliary cavalry at Vingeanne; the Gauls had the worst of it, losing some 3,000 men, but they bought Vercingetorix time to herd all the region's cattle into Alesia.

The town sat atop an oval mesa-like hill, Mount Auxois. The flat top fell off on steep sides, virtually impossible to climb. The city walls were almost an extension of the mountainside. Running east to west above and below the town were the Oze and Ozerain rivers. Vercingetorix had a trench dug on either side of the hill running north-south between the rivers, making an approach to the city almost as difficult as an assault. With his 95,000 soldiers, Vercingetorix was sure Caesar could not possibly harm him.

Caesar's army consisted of 40,000 Roman legionnaires, about 5,000 Germanic cavalry, and about 15,000 auxiliary troops of one type or another. He began the siege sometime in July 52. The Romans dug a trench completely around the hill stretching 10 miles in circumference. The Roman soldier was used to digging: he had done so on every day of every campaign while he had been in the army. It was standard procedure to dig a trench and set up a palisade around camp every evening. The Alesia trenchwork was much more elaborate. It was 15 to 20 feet wide with a 12-foot-high wall and observation towers every 130 feet. To discourage sorties against their lines, the Romans dug more trenches at the foot of the mesa in which they drove sharpened stakes. Interspersed with foot-long wooden blocks with protruding iron rods, these were designed to slow attackers during the day and to disrupt any night foray.

Vercingetorix had dispatched riders just prior to the investment, ordering them to rally the tribes to his aid. If the siege went on too long, the Romans could easily find themselves fighting back Gallic relief attacks while attempting to maintain their siege. Caesar ordered the digging of a line of circumvallation-a second set of trenches and walls outside the first. These stretched for 14 miles and would be a defensive line against a relieving force. Although giving the maximum defensive strength, it had the negative aspect of potentially having his besieging army becoming besieged themselves.

In October the relief force arrived, numbering perhaps 240,000 infantry and another 8,000 cavalry. (Although ancient sources often exaggerate enemy strength, modern historians accept these numbers as fairly accurate.) Caesar gathered whatever food was within foraging distance into his lines and continued the siege. The relief force attacked twice, using ladders and sandbags against the outer trenches, while Vercingetorix led sorties out of Alesia in support. The Romans with difficulty managed to beat back all assaults. The third attack almost succeeded. The Gauls discovered what they thought to be the weakest point of the Roman position, the northwest corner of the outer line. They approached at night, screening themselves behind a hill all morning. When a diversionary attack shifted Roman attention to the south, the northern attack hit. Multiple waves of Gauls pressed the assault, gaining ground then turning the attack over to the next, fresher line of men. The Romans were pressed to the breaking point when the German cavalry struck the Gallic rear. That broke the assault and the Gauls fled. At the height of the battle Caesar led the last reserve into the fight, wearing a bright red cloak so his men knew he was with them.

Food supplies in Alesia were almost gone. Vercingetorix had expelled all civilians and the wounded, but Caesar forced them to stay at the base of the hill, starving. Vercingetorix finally admitted defeat, giving himself to his subordinates to kill him or turn him over to the Romans. The entire force surrendered.

Although the garrison fell into Roman hands, most of the relief force scattered and returned to their homes. Final casualty figures are unknown, but there were enough prisoners for each Roman soldier to be awarded one as a slave; each officer received several. Vercingetorix was taken in chains to Rome, where he was a showpiece in Caesar's triumphal parade. He languished in a cell for six years before he was finally executed.

After Alesia there were no more serious uprisings against Roman rule in Gaul. Caesar in six years succeeded in establishing Roman power in the province, and Gaul proved to be one of Rome's most profitable acquisitions. It also stretched the limits of Roman civilization well past the Italian peninsula. "The siege of Alesia decided the fate of Gaul and the character of French civilization. It added to the Roman Empire a country twice the size of Italy and opened the purses and markets of 5,000,000 people to Roman trade. It saved Italy and the Mediterranean world for four centuries from barbarian invasion; and it lifted Caesar from the verge of ruin to a new height of reputation, wealth, and power" (Durant, Caesar and Christ, p. 177). This may overstate the Gallic threat to Italy; even organized behind Vercingetorix they probably would not have maintained a united effort had they won at Alesia. There were too many tribal feuds for that to happen. Still, it could well have placed Celtic society in northern Italy, where one had been less than a century earlier. Even a disorganized invasion could have wrought immense havoc throughout the Italian peninsula. The great Roman general Marius had built a personal army to turn back a similar invasion in 102 b.c.; perhaps another such leader would have arisen. It probably would not have been Julius Caesar, and the course of Roman history would have been radically altered.

Instead, Caesar was victorious, and his fame provoked the jealousy of the remaining member of the Triumvirate, Pompey. Illegally appointed to be the sole consul (there were normally two), Pompey demanded Caesar return to Rome without his army or be declared a traitor to the Republic. Caesar marched his legions into Italy, crossing the Rubicon River on 11 January 49 b.c. That brought an end to the Republic and laid the foundation for the empire.