The Gauls maintained a warrior mentality, which rarely stood them in good stead when they faced the more disciplined Romans. According to historian of the Celts David Rankin, “There can be little doubt that the military technology of the Celts was inferior to that of the Romans. It was still moulded and guided by the cultural assumptions of the Bronze Age. Their tactics were also too much affected by heroic and traditional ideas to give them good chance of success against the Romans.”17 Although the phalanx formation sometimes employed by Gauls required training and organization, they usually tended to seek glory in individual combat. The constant tribal conflicts may have kept them militarily sharp, but it guaranteed an inability to work together in large numbers.18 This meant that tactically the tight Roman formations would hold together both on the advance and the retreat; it also meant that strategically and politically the Romans could divide and conquer.
The Opponents
THE CHANCE TO FIGHT AND GOVERN THE GAULS would provide Caesar with fame and fortune, both of which he would need to reach the top politically.19 Caesar believed these things stood to be gained in Illyria, a province along the northeastern Adriatic Sea under the authority of Cisalpine Gaul. Defeating barbarians and spreading Roman control into the Balkans would have been sufficient to advance his goals in Rome; however, his last-minute appointment to the governorship of Transalpine Gaul would prove to be even more profitable. Things had been relatively quiet north of the Alps for some time. The stretch of land connecting Italy and Spain, Narbonensis, was occupied to protect the connection between the two major areas of Roman interest; anything to the north was barbarian country, which a Roman governor could often influence by being an unbiased judge in tribal disputes.
Being a mere arbitrator would not bring Caesar wealth or notoriety, so in 58 BC he had to manufacture a reason to launch an expedition into Gaul. The migrating Helvetii gave him that excuse. Caesar claimed that a third of a million people were invading Transalpine Gaul, though in reality they were more likely aiming at relocation to the Atlantic coast for their growing population and because of harassment from Germanic tribes (though Caesar averred that they, too, were Germanic). Caesar refused the Helvetii request for permission to cross the region peacefully, and proceeded to bar their way with troops. When the Helvetii bypassed Roman territory and entered Gaul farther north, passing through the lands of the Aedui, Roman allies, Caesar provoked a battle at Bibracte (Mt. Beuvrey in Burgundy). The Roman army crushed its opponents and captured the Helvetian camp; Caesar claimed that of the original 368,000 Helvetians and allies, only 110,000 returned to Switzerland. The Helvetii had thought of themselves as one of the superior Gallic tribes, but after their defeat at Caesar’s hands they faded into history.20
With his forces now about 150 miles outside Roman Gaul in the neighborhood of the allied Aedui, Caesar responded to the Aedui citizens’ request for protection from Germanic raids by the Suevi (or Suebi) under Ariovistus. Caesar now had little trouble gaining permission from the Senate for more military action. By classifying the Helvetii as Germans and then defeating them, he made all Germans seem to be potential threats.21 Ariovistus, however, was an official Roman ally. A meeting between Caesar and Ariovistus accomplished nothing, as neither was willing to back away. The ensuing battle was another Roman victory, with a reported 80,000 Germans killed.
Rather than remove his troops southward for winter quarters, Caesar left most of them on-site in Aedui. By going into winter quarters on the German frontier, he virtually annexed the lands of the Aedui and Sequani; rather than emerging as their champion against the Suevi, he instead became their new master.22
In 57 BC Caesar’s allies in the Senate secured an extension of his term in Transalpine Gaul, so he continued his conquests by meeting the challenge of the Belgae. The Belgae gathered in a mass near the Aisne River but soon found they could not keep such a large army supplied, forcing them to disperse. Caesar followed the now-separated tribes and proceeded to defeat them piecemeal. The Nervii, however, gave him a scare at the Sambre River. Sixty thousand Nervii men ambushed the Romans and took over their camp, creating chaos among Caesar’s men. Scattered and unprepared, the Roman legionaries formed themselves up alongside whatever soldiers were nearby, ignoring unit designation. Caesar ordered the men into two large defensive squares, and remained in the middle of the action, helping his men’s morale until the 10th Legion, Caesar’s favorite, marched up to provide support. This proved sufficient reinforcement to turn the tide of battle and vanquish the Nervii.23
Caesar’s legions traveled west in 56 BC. He fought the Venetii in a naval battle off the Brittany coast, employing the boarding tactics Romans had used since the Punic Wars. Leaving subordinates to march south and pacify the Aquitani (Aquitaine), he marched back to Belgium. The following year, however, political troubles arose at home. Caesar’s fellow triumvirs and coconsuls were gaining a lot of public recognition while he was away from the capital, and Caesar realized that he needed to stay in the headlines if he was to maintain popular support. He organized a march east against the Germanic Usipi and Tecteri tribes, who had been fleeing the Suevi and crossed the Rhine into Gaul. Using a skirmish between the tribes and a Roman cavalry detachment as an excuse, Caesar and his men slaughtered the fleeing Usipi and Tecteri in their camps. He followed this up with a quick excursion across the Rhine, becoming the first Roman general to enter German territory after his engineers performed a minor miracle by throwing a bridge across the river in ten days. Caesar marched his legions across for a reconnaissance in force for eighteen days, but there was no fighting, and in the end the Romans withdrew back across the Rhine and destroyed the bridge behind them. The Roman general did, however, manage to impress both allies and enemies with the operation, as had been his intention.24
Caesar followed this up by another Roman first. Ramon Jimenez, in his biography of Caesar, describes his most spectacular effort to win public acclaim, an ill-advised and dangerous expedition across the English Channel to Britannia. “Even though Caesar managed to land two legions on the Kentish coast in the face of furious opposition by the Britons, a late summer storm wrecked his ships and blew his cavalry transports back to Gaul. He repaired his ships, but without his cavalry he was unwilling to advance inland.”25 A second, rather more successful invasion took place the following year, but nothing permanent was established other than a target for future Roman expansion.
Caesar spent the campaign season of 53 BC punishing tribes who had ambushed some 5,000 Romans outside modern Liege, as well as some remnant Nervii who attacked another garrison. His retribution was almost as cruel as his treatment of the Usipi and Tecteri. It seems that Caesar’s blend of justice and mercy was showing too little of the latter, and the Gallic tribes began to grow angry and restless—and, eventually, smart. Intertribal squabbling had made them easy targets for too long, so the Gauls finally began to rally around a single leader, Vercingetorix of the Arvernii (modern Auvergne). Almost nothing is known of his background, other than that his father had been executed for trying to unite the tribes. Celtic historian Gerhard Herm describes him: “He was called Vercingetorix and as a man was just that: ver (over)–cinget (warrior)—rix (king); a man who could lead, persuade, and motivate men to great deeds.… Vercingetorix sought not only to regain freedom but to defend his house’s claim to hegemony over the whole country.”26 Although initially expelled from his own people, Vercingetorix appealed to other tribes who realized a new approach was needed in order to fight the Romans. Vercingetorix demanded hostages from each tribe that joined him and killed the kings who refused to provide them. In this chieftain the Gauls had a worthy opponent for Caesar and his legions.27
Vercingetorix at once saw that the main weakness of the Roman military in Gaul was its lack of supplies. When not fighting, Caesar spent most of his time worrying about how to keep his troops fed. The first Gallic target was therefore a major Roman supply dump, Cenabum (Orleans). Vercingetorix led a successful attack, capturing Cenabum
and all of the Roman inhabitants there. This news reached Caesar in Cisalpine Gaul, where he had spent the winter and had recently raised two new legions. Most of his veterans, however, were in the north. Caesar marched with his two legions westward into Transalpine Gaul to Narbo (Narbonne), heartening the subject Helvii and Ruteni tribes. He then went on the offensive.
With his handful of men (but with the veterans under his chief lieutenant Labienus marching from Belgium to his aid), Caesar surprised Vercingetorix by heading through mountain passes still covered with snow and emerging in the Rhone valley. While Vercingetorix was besieging Roman allies in Gorgobina, Caesar distracted him by moving northward and then turning west to recapture Cenabum and seize a number of oppida (hill forts-towns) to scare the Gauls as well as to replenish his food supply. In response, Vercingetorix implemented a scorched earth policy as he withdrew southward. He decided against burning the oppidum of Avaricum (Bourges), however, when the inhabitants convinced him their walls could keep the Romans out. Vercingetorix moved on, and Caesar laid siege to the town. Although he had traveled with siege engines through much of his Gallic campaign, Caesar rarely seems to have been obliged to use them. At Avaricum, however, he quickly proved his mastery of siegecraft, and the Roman soldiers proved to be master excavators. In less than a month, often in downpours, they built two mobile siege towers and a 330-foot-wide, 225-foot-long, 80-foot-high ramp up to Avaricum’s walls. Out of food, in a severe rainstorm, the Romans finally scaled the walls, slaughtered the population, and ate well.
Vercingetorix withdrew further southward into his home territory of the Avernii in south central Gaul and awaited Caesar’s legions at his hometown of Gergovia. Caesar sent Labienus, who had joined him from Belgium, with four legions to subdue the area around modern Paris while he marched in pursuit of Vercingetorix with six legions. Here Caesar suffered one of his few defeats in Gaul. The town of Gergovia was atop a steep hill, making direct assault an impossibility. Caesar hoped to lay a successful siege, but doing so in the midst of the enemy’s homeland was a difficult task. He managed to secure a strong position and build a fortified camp that limited the Gauls’ ability to gather water and forage. However, the defection of Rome’s long-time allies, the Aedui (owing to false reports of massacres by Romans), obliged him to leave about a third of his force in place while he marched away to placate the disaffected tribe. Although he succeeded in reconverting a column that had been marching to join Vercingetorix’s cause, word of the “massacres” was sowing dissension across the region. In Caesar’s absence, the Gauls at Gergovia had pressed his remaining two legions almost to the breaking point.
Caesar needed to get to a more secure location, join Labienus, and decide on his next move. However, a precipitous withdrawal would result in bad publicity. He could make no move that implied any weakness, for fear that even more tribes might arise against him.28 He therefore decided to launch a last raid on the outer defenses and gain a quick though minor victory, in order to make the withdrawal appear voluntary rather than forced. He cleverly diverted the bulk of the defenders to the far side of town by disguising mule drivers as cavalry, allowing the Romans to capture the first wall. The speedy capture, however, encouraged the Roman troops to force a passage into Gergovia—against orders, according to Caesar.29 Many Romans were caught inside the town; hundreds were lost. Caesar withdrew, and his fears were realized as many wavering tribes sided with Vercingetorix.30
The Siege of Alesia
CAESAR MARCHED TO LINK UP WITH LABIENUS and to replace his locally raised cavalry with Germans. He recruited a good force and provided them with more serviceable local horses. As he was doing so, word arrived of Vercingetorix attacking Gallia Narbonensis in the south. Caesar had no choice but to march to defend Roman territory.31 In a battle in the homeland of the Allobroges, the newly arrived German cavalry proved decisive in defeating the Gauls. In response, Vercingetorix banked on the growing support of tribes across Gaul and retreated into the interior, finally coming to a halt at the oppidum of Alesia (Alise-Ste.-Reine),32 which sat on a flat-topped mesa.33 Vercingetorix’s retreat to this interior location has been seen variously as both foolish and tactical; in their history of Rome, M. Cary and H. H. Scullard call it “the fatal mistake,” while in her work on the Gallic Wars, Kate Gilliver’s view is that Vercingetorix “allowed himself to be hemmed in… to catch the Roman army in a pincer movement.” Hans Delbrück says it was a refuge to stem the flight of the Gauls after their most recent defeat, while Warry suggests Vercingetorix was trying to repeat his victory at Gergovia,34 for Alesia was also impossible to assault directly. Whatever the reason behind Vercingetorix’s move, when Caesar arrived at Alesia he began an encirclement, setting the stage for what would become the greatest siege since Alexander at Tyre.
Caesar asserts that Vercingetorix went into the fortress with 80,000 soldiers. Like all numbers Caesar gives in his writings, one has to take it with a few grains of salt. Delbrück agrees with Napoleon III (who idolized Vercingetorix as a French hero) that keeping 80,000 men inside Alesia made no sense, for maintaining that number in addition to the civilian population for more than a month would be impossible. Napoleon surmised that had he had that many men, Vercingetorix would have either sent out 60,000 to harass the Romans and keep them from their construction and foraging, or else would have encamped them below the city to launch sallies prior to, or even after, being encircled. Military historian Richard Gabriel believes it more likely that Vercingetorix started the siege with 10,000–15,000 cavalry on hand. Plutarch, however, goes even further in his estimate than does Caesar, claiming 170,000 inside Alesia.35
The number Caesar had under his command also is the subject of discussion. Delbrück writes that “Caesar had 11 legions, Numidian and Cretan sharpshooters and German cavalry and light infantry, for a total of perhaps 70,000 men.” All other modern sources report ten legions. How many auxiliaries (especially German cavalry and light infantry) were on hand is undisclosed, though there were enough to beat back occasional Gallic raids during the siege and be the arm of decision against a reported 8,000 relieving cavalry.36
The most important thing about the siege was the engineering. Caesar may not have introduced new technology as Alexander did at Tyre, but he made the best use of what was known at the time, as well as of the physical labor abilities of the Roman infantryman. The Alesia mesa was extremely difficult to reach; it was bounded north and south by the Ose and Oserain Rivers and the walls of the mesa fell steeply to the banks, and to the east a saddle stretched over to Mt. Penneville, which was covered by Roman earthworks. Only to the west was there a plain and thus an area for a sally from the hilltop. The initial Roman works were constructed on the west face of the oppidum, where the Romans dug a ditch connecting the two rivers. It was six meters wide with sheer sides six meters deep. The start of the main defense line was 400 paces (just under 600 meters) further west. Warry describes the western defenses: “Here, there were two trenches each 15 [Roman] feet (4.4m) wide and 8 feet (2.4m) deep; the river was diverted to carry water into the inner trench wherever possible. Behind the trenches was a 12-foot (3.6m) earthwork and palisade, with antlered prongs projecting from it. Breastworks and battlements were overlooked by turrets at intervals of 80 feet (23.6m).”37
The earthworks encircled the mesa, a process known as contravallation, to a length of 11 Roman miles (10.1 mi. or 16.3 km). To make a sally even more difficult, the Romans placed booby traps in the approaches, “all having names that indicate the black humour with which soldiers often look at their profession. There were five rows of sharpened stakes woven together so that they could not be uprooted, which were called cippi (‘tombstones’); then several rows of V-shaped pits that concealed fire-hardened stakes referred to as lilia (‘lilies’); and in front of these were 30 cm (11 in) stakes embedded diagonally in the ground with iron barbs protruding from the top, known as stimuli (‘stingers’).”38
Vercingetorix, after launching an early and unsuccessful sally agai
nst the Romans, had his cavalry sneak out before the encirclement was complete. They were to rally the tribes to march to relieve the siege. Time was of the essence, as there was only a thirty-day supply of grain and limited cattle. Why Vercingetorix did not immediately burn the fields after having gathered in the supplies is hard to fathom, since he had previously and successfully used scorched earth tactics. When Caesar learned from deserters that a relief effort was being mounted, he put his soldiers back to work digging yet another wall to encircle the encirclement—known as circumvallation. This wall mirrored the first in style and stretched 14 Roman miles (12.9 mi. or 20.7 km). Lilia and stimuli were strewn outside this wall as well, but not to the extent that the interior was prepared. Caesar ordered his men to gather food and forage for thirty days.
As the food in Alesia began running out, a Gallic council of war met to decide the next step, should the relief force arrive too late or not at all. Critognatus, one of the chief officers, suggested cannibalism. Vercingetorix vetoed that idea, at least temporarily and, according to Cassisus Dio, instead “thrust out the children and the women and the most useless among the rest.”39 Those poor souls, whose number is unrecorded, had to huddle between the stone walls of Alesia and the wooden walls of the Romans, watching the battle and starving since neither side would or could afford to feed them.
Soon thereafter the Gallic relief force arrived. Caesar recorded, “All march to Alesia, sanguine and full of confidence: nor was there a single individual who imagined that the Romans could withstand the sight of such an immense host: especially in an action carried on both in front and rear.”40 Forty-two tribes numbering 8,000 cavalry and a quarter million infantry came to Alesia’s aid, or so Caesar claimed; as usual this provokes much debate. Delbrück argues that such a number could have been rallied, but most of the men would have been untrained militia. “If a Gallic commander had been capable of operating with an army of 250,000 men, it would remain an unpardonable, completely incomprehensible error on the part of Vercingetorix not to have assembled this army from the start and with such superiority to have sought an open battle.”41 While most commentators agree that this number is exaggerated, the advancing army was undoubtedly large; perhaps more than 100,000 strong.
Masters of the Battlefield Page 14
