Julius Caesar: The Last Dictator

	" It was clearly impregnable except by blockade; for it stood at a high altitude on top of a hill washed by streams on the north and south, and closely surrounded by other hills as high as itself on every side except the west, where a plain extended for some three miles. The whole of the slope below the town ramparts on the east was occupied by a camp crowded with Gallic troops, who had fortified it with a trench and a six-foot wall. The siege works that the Romans were starting to make had a circumference of ten miles. Eight camps were placed in strategic positions, linked together by fortifications along which twenty-three redoubts were built. The redoubts were occupied in the daytime by pickets, to prevent a surprise attack at any point; at night strong garrisons bivouacked in them with sentries on duty."
	Caesar The Gallic Wars , VII, 69

Near the quiet modern-day town of Alise-Sainte Reine in France, 32 miles northwest of Dijon, Gaius Julius Caesar fought one of history's legendary battles. His opponent, Vercingetorix, an Avernian chieftain, had raised a great confederacy of Gallic tribes to hurl the Romans once and for all from their war-torn lands. Caesar's legions were outnumbered by their enemies roughly six to one. He had built a series of fortifications around the isolated fortress of Alesia which was considered breathtaking even by Roman engineering standards -not one, but two, great circumvallations totaling between 10 and 13 miles each. Atop Alesia, Vercingetorix's tribes attacked; outside the perimeter fortifications, a giant Gallic army arrived in support. Caesar was fighting the combined might of Gaul in two directions at once. Yet his victory at Alesia and the surrender of Vercingetorix was so complete that many historians view the siege as definitive in the bloody attempt to impose Roman rule on "Long-haired Gaul." Caesar's final two years in the province were, after Alesia, largely mopping-up operations. The tribal confederacy was broken at Alesia: it never recovered.

THE GALLIC CONFEDERATION

In the winter of 53-52 BC, Caesar was in Cisalpine Gaul holding the normal pattern of judicial assizes, when he suddenly learned that the Carnutes, hitherto thought largely pacified, had massacred all Roman citizen traders as well as Caesar's commissariat officer in their oppidum of Cenabum (Orleans). Caesar did not yet know that a majority of the Gallic tribes had united under a young Avernian nobleman, Vercingetorix, who planned a combined and final effort to destroy Caesar's legions in Gaul. Caesar immediately crossed the Alps and the heavy snows of the Cevennes mountains, appearing in the center of France long before he was expected. He concentrated his legions around the region of Agedincum (Sens).

Dividing his troops, Caesar led six legions in the direction of Gergovia, the main stronghold of the Averni, while Titus Labienus took four legions to quell the rebellion closer to the north, near Paris. Meanwhile, Vercingetorix, manning the strong natural fortress of Gergovia, had secured the support of the vital Aedui tribe and its leader, Commius, once considered one of Caesar's most dependable allies. This negotiating triumph led immediately to the massacre of Roman troops by 10,000 supposedly loyal Aedui cavalry and additional murders of all Roman citizens in Cabillonum (Chalon-sur-Saone). Caesar's attempt to defeat Vercingetorix before Gergovia led to as near a military defeat as he ever suffered in Gaul, and he was forced to withdraw. The Gauls torched the army depot of Noviodonum, massacred its Roman merchants and Caesar's hostages, and continued attacks on Caesar's supply lines although without a breakthrough. Caesar fell back toward the Loire, although he managed to successfully reunite with the legions of Labienus and find some breathing room to replenish his cavalry with German (not Aeduan) auxiliaries.

The view from Caesar's lines to the plateau

Vercingetorix was persuaded to invest the citadel of Alesia following his unsuccessful attacks on Caesar's legions by cavalry attack. He withdrew his army (allegedly 80,000 strong) to the great hillside fortress of Alesia. Caesar quickly grasped the changed situation and followed,beginning on his arrival that inexorable enclosure of the hilltop fortress which would isolate Vercingetorix's army from its remaining allies.

THE SIEGE, 52 BC

	" Most of the people who escaped from the battle took refuge with their King in the city of Alesia. The place was regarded as impregnable because of the size and strength of the walls and the great numbers of its defenders. Caesar besieged it, however, and while doing so, was threatened from outside by a quite indescribable danger. Three hundred thousand men, the best fighting troops from every nation in Gaul, assembled together and marched to the relief of Alesia. Caesar now found himself caught between two enormous forces; he was himself besieged and was compelled to build two systems of fortification, one facing the city and one facing the relieving army, since he knew well that, if the two forces should combine, everything would be over with him. "
	Plutarch, Life, 27

With Caesar's fabled focus on the arts of engineering to defeat his enemies, he proceeded to circumvallate around the entire plateau of Alesia, constructing walls, ditches, and all the concomitant structures which would lock in the Gauls. The first series of walls eventually stretched a total length of 10 miles. An 18-foot-wide ditch was backed by a second trench, filled with water from a nearby source. Then came a series of buried iron "mantraps" and carefully concealed holes in the ground, several feet deep, containing pointed stakes in the center that would easily impale. A third wall, far behind the others, was nine feet high and capped with breastworks. Square towers at regular intervals held the Romans' feared siege equipment. As Caesar expected that Gallic reinforcements would arrive to aid the besieged army, he then turned to face away from the city, constructing an entire second line of fortifications parallel to the first, between 13-15 miles long. The effect was not only to surround Alesia, but also to enclose Caesar's army between the inner and outer rings of fortifications. It was believed at the time, and remains, one of the Romans' greatest feats of wartime engineering, in a league with Masada and other structures which led the foes of Rome to simply disbelieve the evidence of their own eyes.

Sketch of the double circumvallation at Alesia

Vercingetorix was not idle as he saw the walls begin to rise below him. Ongoing cavalry battles constantly interrupted construction and Roman efforts to gather supplies. Warriors regularly issued from the great gates of Alesia to kill and seek a breakout of the tightening siege. However, the increasing waves of defensive fortifications, including mantraps, made it more and more dangerous for anyone venturing outside the walls. Finally, as Caesar wrote,

	" Vercingetorix now decided to send out all his cavalry in the night, before the Roman entrenchments were completed. He bade them go every man to his own country and impress for service all the men of military age. He pointed out how much they owed him ...[and that] they ought not to abandon him to the cruel vengeance of the enemy. Moreover, if they were slack in doing their duty, they would condemn eighty thousand picked men to perish with him. He had taken stock of the corn, he said, and by strict rationing would have enough for a month - even a little longer, if the ration were reduced. "
	Caesar, The Gallic Wars, 71

Escaping through a gap in the lines, the troops raced to raise reinforcements. During the next month, Vercingetorix forced all the supplies in Alesia to be brought to him and carefully doled them out. Supplies began to run low. With practical cruelty, it was decided to eject from the hilltop fortress all the townspeople - women, children, the aged and those who could not bear arms - so that their rations might go to sustain the warriors within the town. Unfortunately, these miserable people starved between the lines, neither side being willing to accept them into their ranks. Caesar posted guards to ensure that his troops, hearing their cries, would refuse the Mandubrii admission. Meanwhile, the tribes, alerted by the escaped cavalry, had met and, some quarter million strong according to Caesar, marched for Alesia. Modern scholars believe the number of tribesmen was actually between 80-100,000 warriors. Commius and the other allied leaders encamped on a hill a mile outside the Roman outer lines. Caesar with his lieutenants, including Marc Antony and Gaius Trebonius, braced themselves for a two-front battle. The watchers in the citadel cheered when they saw the Gauls arrive. The endgame of Alesia had begun.

"As long as the Gauls were at a distance from the entrenchments, the rain of javelins which they discharged gained them some advantage. But when they came nearer they suddenly found themselves pierced by the goads or tumbled into the pits and impaled themselves, while others were killed by heavy siege spears discharged from the rampart and towers. Their losses were everywhere heavy and when dawn came they had failed to penetrate the defenses at any point...The besieged lost much time in bringing out the implements that Vercingetorix had prepared for the sortie and in filling up the first stretches of trench, and before they reached the main fortifications heard of the retreat of the relief force, so they returned into the town without effecting anything." De Bello Gallico, VII, 83.

Reconstruction of the Alesia fortifications

"It opened on the first day with a cavalry battle, which again ended in a Roman victory thanks to the impetuous valor of the Germans. After a day's rest the Roman fortifications were simultaneously attacked from inside and out, but they were nowhere pierced. Around midday on the fourth day the final storm burst; both besieged and relievers put forth their utmost efforts. On this occasion, too, after a fearful battle, the Romans came through victorious. The great relieving army scattered after the lost of 74 standards. On the next day, Vercingetorix surrendered." M. Gelzer.

On the final day of battle, the irony of the revolted Aeduii cavalry became even more clear: the Gauls lost the battle when Caesar's German cavalry attacked from the rear at the moment of Caesar's charge in front. The warriors wavered, broke, and fled in complete rout, hotly pursued by the brutal German cavalry.

"Vercingetorix gathered the tribal leaders and offered either to die at their hand or surrender, at their choice. He told them, Caesar wrote, that "I did not undertake the war...for private ends, but in the cause of national liberty." A deputation was sent to Caesar, who ordered the defeated Gauls to hand over their arms and bring all tribal chiefs to him. He seated himself at the fortification in front of his camp, and there the chiefs and Vercingetorix were brought to him. As Plutarch writes, "Vercingetorix...put on his most beautiful armor, had his horse carefully groomed, and rode out through the gates. Caesar was sitting down and Vercingetorix, after riding round him in a circle, leaped down from his horse, stripped off his armor, and sat at Caesar's feet silent and motionless until he was taken away under arrest, a prisoner reserved for the triumph." Plutarch, Caesar, 27.

The surviving Gauls on the field were divided among Caesar's soldiers as slaves, after 20,000 Aedui and Averni had been separated from them; the political importance of these tribes was such that Caesar pardoned their warriors and even granted the Aedui their former status as free allies. The Arverni were given relatively easy terms of surrender in return for hostages. This preferential treatment of the two leading tribes, as Caesar intended, secured their future loyalty to Rome by the mercy of Caesar.

	"Thus this remarkable siege was brought to an end by the simultaneous defeat of two armies by a single army, no greater than the one and incomparably smaller than the other. An army which not only was the besieger but itself was besieged, and which had to hold 25 miles of entrenchments in order, at one and the same time, to achieve its aim and secure itself against defeat. In spite of the paucity and frequent vagueness of details provided by Caesar, and the consequent difficulty in reconstructing some of the incidents, the siege of Alesia remains one of the most extraordinary operations recorded in military history.
	J.F.C. Fuller, p.157.

The Senate awarded Caesar a 20-days' thanksgiving in Rome. In the two-year balance of his command, Caesar completed the pacification of Gaul. By the time he crossed the Rubicon in January, 49 BC, what is now France and Belgium were a province of Rome. No later rebellion shook it significantly until the Empire's last decline, four centuries later. Vercingetorix was led, an honored prisoner, into Roman captivity. He remained alive for six years while Caesar fought Pompey in the Civil War and took control of the Roman world. Then, as was customary with a hostage of such notorious valor, he marched stoically in Caesar's Gallic triumph in 46 BC. He was then strangled, again following custom, in the depths of the Mamartine Prison in Rome.

Nineteen centuries later, the Emperor Napoleon III of France, deeply suspicious of the danger of war with Germany and mindful of the tactical effect of Caesar's German cavalry on the defeat of Vercingetorix, stationed a massive statue of the great Gaul on the site of the newly-discovered ruins of the Alesia fortifications. Vercingetorix had come to symbolize the courageous valor of France against its enemies. However, his defeat at Alesia signaled the destruction of all native hopes for an independent Gaul.

SOURCES: J.F.C. Fuller, Julius Caesar: Man, Soldier and Tyrant. Image of Vercingetorix by kind permission of James Grout, Encyclopaedia Romana; Sketch of entrenchments from Alesia; watercolor sketch from Gymnasia Laurentianum;