Julius Caesar took official command of his provinces of Illyricum, Cisalpine Gaul and Transalpine Gaul in 59 BC. His original desire was likely to pursue glory against the further reaches of Illyricum and Dacia, but events in his new provinces soon changed the plan.
In Gallia Narbonensis, the stretch of southern France connecting Spain to Italy, the Gallic people had largely been assimilated into Roman culture over the course of the last century. Beyond this territory to the north was a vast land comprising modern France, called Gallia Comata (long-haired Gaul), where loose confederations of Celtic tribes maintained varying relationships with Rome.
These Celtic tribes, while primitive compared to the standards of Rome, traded abundantly between themselves and the Roman frontiers. For the most part, a general peace reigned between the tribes and Rome for the better part of the last century, but external pressures from Germanic tribes started unsettling the relative calm.
The Romans, however, had a long memory, and fear of Gallic invasions that led to the sacking of Rome in the early 4th century BC was ever present. Additional tribal migrations of the Germanic Cimbri and Teutons in the late 2nd century BC, though defeated by Caesar's uncle Gaius Marius, merely confirmed these fears.
If the Romans had legitimate fear over potential problems with the Gauls, then they were terrified of the wild, uncivilized Germanics. The Celts too, according to Caesar, were apparently despised by the Germanics for their more refined (weak) culture, and also had reason for concern. While Caesar was Proconsul of Spain between 61 and 60 BC, there was already considerable unrest on the Gallic frontier. The Germanic leader Ariovistus had invaded Gaul and raided the border regions, but Caesar quelled the situation at that point by arranging an alliance with the Germans.
Early in his Gallic governorship, Caesar misread the situation and had three of his four legions stationed in Illyricum, but he would soon come to the realization that the real danger and opportunity was in Gaul. Understanding the emotional link that the Roman people had with the people of this region, Caesar began to alter his objectives. He was also likely quite aware of the great trade routes that the Rhodanus (Rhone), Rhenus (Rhine) and Sequanus (Saone) rivers provided. These rivers very well could have provided the most important exterior trade routes in the Roman world. Vast raw materials could be shipped in from the North and North West, while a booming market in Roman luxury items was beginning to go the other way.
Gaul too, was a veritable gold mine in potential plunder. Caesar, though at times showing a moderate respect for Roman law, would need a viable excuse to advance north and avoid legal issues in Rome. Within a short time of his arrival, an excellent opportunity for military glory and to further strengthen his bond with the Roman people would present itself.
A Celtic tribe living in modern day Switzerland, the Helvetii, were at the time under pressure themselves from various Germanic tribes in the area. Under their chieftan Orgetorix, they had planned a move from the Alps region to the west of modern France, or Aquitania. In order to make such a move, however, the Helvetians would have to march not only through Roman controlled territory, but that of the Roman allied Aedui tribe as well. Other Gallic Celts and people within the province of Gallia Narbonensis feared that the Helvetii wouldn't just move through as they proposed, but would plunder everything in their path as they went. Without question, Caesar opposed the idea and hastily recruited two more fresh legions in preparation.
Before the Helvetii marched however, Orgetorix died, but the planning for the move continued. Several other local tribes joined the Helvetti in lesser numbers making the entire force among the largest and most powerful in all of Gaul. In total, according to Caesar, nearly 370,000 tribesmen were gathered, of which about 260,000 were women, children and other non-combatants. Before leaving, the Helvetii burned their villages and destroyed what foodstuff and other commodities could not be taken along. The intention was to make certain that they continued to their destination against all odds.
After setting off, and disregarding Caesar's objection, the two forces inevitably met. After several skirmishes, Caesar occupied the high ground with his six legions, and lured the enemy into a poorly matched battle. Somewhere near the Aedui capital of Bibracte, Caesar crushed the Helvetii, slaughtering the enemy wholesale with little regard for combat status. According to Caesar himself, of the 370,000 enemy present, only 130,000 survived the battle. In the next few days following the battle while chasing down the fleeing enemy, it seems that at least another 20,000 were killed. While the numbers may very well have been exaggerated, there is no doubt of the slaughter. In all, nearly 260,000 people, including a great many women and children, were reportedly killed. While today this may seem an atrocity, to the Roman people these Helvetii, seemingly mistaken for Germanics, were considered the barbaric enemy deserving of no better fate.
Caesar's great victory left him with other problems however. First, he forced the Helvetii back to their home land to prevent more Germanic incursions into what had become open land. Next, he allowed the somewhat friendly or at least pacified Boii tribe to settle into a buffer zone with the Aedui and the Helvetii.
The weakened state of these southern Gallic tribes, though, thanks to Caesar's conquest, left parts of Gaul open to Germanic incursions. A federation of tribal leaders came to Caesar to ask assistance against their old nemesis Ariovistus and his Suebi tribesmen. Certainly not noting the irony of his actions against the Helvetii, Caesar's own words describe the despair of one particular tribe, the Sequani, who faced the raids and occupation of Ariovistus. Seeing the obvious potential for further glory, under the pretense of responding to calls for help, he then took the opportunity to protect his Gallic 'friends'.
Ariovistus and the Suebi
As Ariovistus made incursions against the Roman allied Gallic Celts, Caesar sought initially to resolve the matter diplomatically, at least according to his writings. Ariovistus, the Suebi chief, had already conquered much of eastern Gallic territory only a few years prior, but Caesar was able to reverse the situation through diplomacy. Ariovistus was named a friend and ally of the Roman people, but this relationship proved to be short lived. Caesar's initial attempts in 58 BC to negotiate with the Germanic were defiantly rebuffed. Ariovistus it seems, viewed this part of Gaul as his territory, and Caesar's presence was considered a violation of their treaty. Caesar quickly recruited additional forces and prepared for the impending conflict. Additional missions sent to end the stand off diplomatically were failures.
Caesar estimates that over 120,000 Germanic warriors had crossed the Rhine into Gaul at this point, occupying the land of the Sequani and harassing the Aedui, as well as other tribes. Caesar received word that additional warriors were crossing the Rhine to siege the Sequani town of Vesontio, so he made haste to garrison the town. By the time the enemy arrived, the Romans were safely entrenched, and Ariovistus decided to open negotiations.
Caesar and the Germanic chief met face to face to discuss the situation, but little was accomplished. Ariovistus argued that he had as much right as the Romans to conquer and control in order to prevent additional warfare. Caesar, whilst acknowledging this very simple and parallel Roman principal, suggested that Ariovistus' rights were null and void due to his failure to help against the Helvetii. It was quite clear that neither side was going to back down from the other and war was a foregone conclusion.
Caesar, however, encountered new problems. His legions, now in such proximity to the wild Germans, were suffering from terrible morale. Any battle to come would surely result in panic from his men in the face of the enemy's ferocity. Caesar delivered a rousing speech specifically praising his famous 10th legion, and suggesting that if the others were too frightened, he would go into battle with only this one. Being called out by the beloved commander, as he would do often to quell trouble in the future, settled the men and they were thereafter eager to join the coming fight.
Somewhere near modern Besancon, with all diplomacy exhausted, the Romans and the Germanics finally met in battle, sometime in September of 58 BC. Impatient at delaying tactics employed by Ariovistus, Caesar launched a full assault on the enemy camp. He himself accompanied his right wing which seemingly would need the most support. The battle that followed was an epic struggle between two well matched armies.
Caesar wrote that his men fought valiantly, sweeping the Suevi on the left flank:
"There were found very many of our soldiers who leaped upon the phalanx, and with their hands tore away the shields, and wounded the enemy from above. Although the army of the enemy was routed on the left wing and put to flight, they pressed heavily on our men from the right wing, by the great number of their troops."
Seeing the trouble on the right, Caesar's young lieutenant Publius Licinius Crassus, son of the triumvir, led a cavalry charge that turned the tide in Roman favor. The Suevi were routed on the field, with estimates as high as 25,000 being killed. The survivors rushed back to the Rhine to cross back home, including Ariovistus who escaped in a small boat.
The surviving Suebi then had to deal with another Germanic tribe, the Ubii, who harassed and attacked them as they returned home. The Suebi survived to fight another day however, and Caesar would be forced to face them again just a few years later. Unfortunately, Caesar never mentions the fate of Ariovistus, but having concluded two very important wars in one campaign season, Caesar put his army into winter quarters among the Sequani. He appointed Labienus in command, and set out in person for Cisalpine Gaul to attend to political business.
In the spring of 57 BC, Caesar was in Cisalpine Gaul attending to the administration of his governorship. Despite - according to Caesar - cries of great thanks from various Gallic tribes for deliverance from the Suebi, discontent was growing. Word came to Caesar that a confederation of northern Gallic tribes was building to confront Roman presence in Gaul.
It is important to note, though, that Caesar, by this time, had probably realized the only way to maintain the territories in eastern and southern Gaul, was to conquer the whole of the province. It's convenient for Caesar that these northern Belgic tribes would muster against the Romans for no reason, unless of course, they had reason to believe the Romans weren't done with expansion. Whatever the truth, Caesar hurried back to his legions, raising two new legions (the 13th and 14th) in the meantime, bringing his total to eight.
As Caesar arrived, likely in July 57 BC, the rumors of Belgae opposition proved true. Caesar moved quickly, surprising the Remi before they could join the opposition, and made fast allies of them. The Belgae, in reprisal against this, began to attack the town of the Remi. At the Remi town of Bribrax, Caesar moved en masse to protect it from Belgae aggression. In an example of Caesar's brilliant ability to out-march any known army, he surprised the enemy. With eight legions, the Romans crushed the attack in a hard fought affair.
The victory was two fold for Caesar. It not only was a victory in the field, but a political and propaganda win as well. By defending his 'allies' from external aggression, he could now easily secure the necessary legalities to continue aggression against the Belgae. Though it would be another difficult campaign, this was exactly the sort of fortune that Caesar wanted.
After securing the town of Noviodunum and territory of the Suessiones, Caesar learned that the fearsome Nervii, with the Atrebates, Veromandui and Aduatuci, were forming against him on the opposite side of the Sambre River. The main part of the Roman army were in the midst of making camp along the river, while the two newest legions were bringing up the rear with the slow moving baggage train. Caesar sent out his cavalry to scout the situation, apparently unaware of the massing enemy preparing for ambush in the surrounding forests. The gathering Belgae, seeing Titus Labienus leading the Roman cavalry away, launched a complete surprise attack, storming the shallow river and pouncing on the unsuspecting Romans. The fighting was immediately desperate and the legions were hard pressed to maintain their ground. The Nervii and their allied tribes nearly surrounded the Romans, threatening the camp and the utter destruction of Caesar's army. Caesar's timely intervention, however, personally standing and fighting with his men, helped Roman discipline maintain itself.
In a nearly disastrous battle that could have changed the history of Europe, three things in particular kept the Romans from absolute defeat. Caesar's own personal intervention was important in stabilizing the men, the two legions with the baggage train arrived just in time to reinforce crumbling Roman lines, and the return of the Roman cavalry.
Titus Labienus had taken the enemy camp in the midst of the fighting and was positioned at a vantage point where he could see the entire battle unfolding. He ordered Caesar's favorite 10th legion, no longer in danger itself, into a critical part of the enemy lines, relieving their distressed comrades. Soon after, the enemy lines broke and the Belgae warriors were in mass flight.
According to Caesar, though the numbers are assuredly in doubt, the Nervii surrendered and informed him that of 60,000 original warriors, only 500 remained. With the promise of no more aggression, he allowed them and other tribal combatants to return to their lands as subjects of Roman power.
The Aduatuci however, arriving late to the battle, fled intact to their lands and Caesar pursued. Arriving at the Aduatuci fort, where the tribe had walled itself in, Caesar showed a strategic brilliance in siege warfare that would be culminated at Alesia five years later.
The Romans laid siege, building a 15 mile wall 12 feet high around the fort, and constructed siege weapons with which to ram the Aduatuci walls. Prior to complete destruction, Caesar offered peace and freedom to maintain their lands if only they would submit and give up their arms. Initially the tribe agreed, casting their weapons out of the fort and opening the gates to the legions.
Caesar then suggests that after confirming the surrender, he ordered his men out of the fort for the night, to prevent unnecessary looting or injury to the Aduatuci. During the night however, thinking that the Romans would lower their guard in light of the surrender, the Aduatuci stormed the Roman lines, hoping to catch them by surprise. The attempt failed and nearly 4,000 men were killed, with the rest retreating to the fort. In the first of many perceived brutalities, Caesar would be merciless. The next day the Romans stormed the fort, capturing it quickly. He then claimed that 53,000 people were captured and sold into slavery, virtually wiping out the Aduatuci.
At this point, Publius Licinius Crassus returned, who had been sent against the Veneti, the Unelli, the Osismii, the Curiosolitae, the Sesuvii, the Aulerci, and the Rhedones of Brittany and Normandy. He informed Caesar that this northwestern section of Gaul was completely under Roman dominion. Though this assessment was not quite true, it served Caesar's purpose for the time being.
He next negotiated cooperation with various bordering Germanic tribes to ensure the stability of his gains. Word was sent back to Rome, and despite opposition to his politics, Cicero himself pushed through an unusual Supplicatio, or public offering of thanks, for Caesar. A typical Supplicatio lasted only 5 days, and Pompey received 10 days for his conquest of the east. Caesar however received 15 days, marking a very strange concession to the man who was so reviled by the Senatorial conservatives.
After putting most of his army into winter quarters, Caesar then moved to his third province of Illyricum to attend to matters there, while his lieutenant, Galba, secured passes through the Alps by defeating resistant Seduni tribes.
Conquest of Gaul
As the campaign year of 56 BC opened, Caesar found that Gaul still wasn't quite ready for Roman occupation. In his own words: "he reflected that almost all the Gauls were fond of revolution, and easily and quickly excited to war; that all men likewise, by nature, love liberty and hate the condition of slavery, he thought he ought to divide and more widely distribute his army, before more states should join the confederation."
Labienus was sent with the bulk of the cavalry among the Treveri which was near the Rhine. He was charged with keeping peace among the Belgae and preventing Germanic crossings into Gallic territory.
Publius Licinius Crassus was sent to Aquitania with twelve legionary cohorts to subdue the tribes there. With the help of Gallic auxilia, as in all cases, Crassus quickly brought Roman control to the westernmost portion of Gaul. Though with some difficulty, Crassus won two decisive battles over the Sotiates followed by the Cantabri. When word passed through the region of the Roman victories, it encouraged the rest of the region to surrender peacefully. In short order, the Tarbelli, Bigerriones, Preciani, Vocasates, Tarusates, Elurates, Garites, Ausci, Garumni, Sibuzates and Cocosates all surrendered to Roman domination.
In the north, Caesar ordered Q. Titurius Sabinus with three legions to quell any potential opposition among the Unelli, Curiosolitae, and the Lexovii. Sabinus made short work of any resistance and brought his territory under Caesar's sway. Decimus Brutus, the young future assassin of Caesar, was sent to build a fleet amongst the Veneti.
This move, while certainly designed to establish authority over the whole of Gaul, was a certain precursor to the invasion of Britain. The Veneti controlled the waterways with a formidable fleet of their own and were augmented by British Celts. At first the Gallic vessels outmatched the Romans, and Brutus could do little to hamper Veneti operations. Roman ingenuity took over, however, and they began using hooks launched by archers to grapple the Veneti ships to their own. Before long, the Veneti were completely defeated, and like many tribes before them, sold into slavery.
With the defeat of the Gallic resistance, Caesar next began to focus his attention across the channel. Still, the conquest was not quite as complete as it seemed. First Caesar would have to deal with more Germanic incursions before he could cross to Britain. And despite his confidence, the Gallic tribes were not nearly as subdued as he thought. For now, though, Caesar returned to Cisalpine Gaul to attend to political matters in Rome.