Cæsar set out for his province immediately after Cicero had gone into exile (B.C. 58). During the next nine years he was occupied with the subjugation of Gaul. In this time he conquered the whole of Transalpine Gaul, which had hitherto been independent of the Romans, with the exception of the part called Provincia. Twice he crossed the Rhine, and carried the terror of the Roman arms beyond that river. Twice he landed in Britain, which had been hitherto unknown to the Romans. We can only offer a very brief sketch of the principal events of each year.
First Campaign, B.C. 58. - Cæsar left Rome toward the latter end of April, and arrived in Geneva in eight days. His first campaign was against the Helvetii, a Gallic people situated to the north of the Lake of Geneva, and between the Rhine and Mount Jura. This people, quitting their homes, had passed through the country of the Sequani, and were plundering the territories of the Ædui. Three out of their four clans had already crossed the Arar (Saône); but the fourth, which was still on the other side of the river, was surprised by Cæsar and cut to pieces. He then threw a bridge across the Arar, followed them cautiously for some days, and at length fought a pitched battle with them near the town of Bibracte (Autun). The Helvetii were defeated with great slaughter, and the remnant compelled to return to their former homes.
This great victory raised Cæsar's fame among the various tribes of Gauls, and the Ædui solicited his assistance against Ariovistus, a German king who had invaded Gaul, and was constantly bringing over the Rhine fresh swarms of Germans. Cæsar commanded Ariovistus to abstain from introducing any more Germans into Gaul, to restore the hostages to the Ædui, and not to attack the latter or their allies. A haughty answer was returned to these commands, and both parties prepared for war. Cæsar advanced northward through the country of the Sequani, took possession of Vesontio (Besançon), an important town on the Dubis (Doubs), and some days afterward fought a decisive battle with Ariovistus, who suffered a total defeat, and fled with the remains of his army to the Rhine, a distance of fifty miles. Only a very few, and, among the rest, Ariovistus himself, crossed the river; the rest were cut to pieces by the Roman cavalry.
Second Campaign, B.C. 57. - The following year was occupied with the Belgic war. Alarmed at Cæsar's success, the various Belgic tribes which dwelt between the Sequana (Seine) and the Rhine, and were the most warlike of all the Gauls, had entered into a confederacy to oppose him, and had raised an army of 300,000 men. Cæsar opened the campaign by marching into the country of the Remi, who submitted at his approach. He then crossed the Axona (Aisne), and pitched his camp in a strong position on the right bank. The enemy soon began to suffer from want of provisions, and they came to the resolution of breaking up their vast army, and retiring to their own territories. Hitherto Cæsar had remained in his intrenchments, but he now broke up from his quarters and resumed the offensive. The Suessiones, the Bellovaci, and Ambiani were subdued in succession, or surrendered of their own accord; but a more formidable task awaited him when he came to the Nervii, the most warlike of all the Belgic tribes. In their country, near the River Sabis (Sambre), the Roman army was surprised by the enemy while engaged in fortifying the camp. The attack of the Nervii was so unexpected, that before the Romans could form in rank the enemy was in their midst: the Roman soldiers began to give way, and the battle seemed entirely lost. Cæsar freely exposed his own person in the first line of the battle, and discharged alike the duties of a brave soldier and an able general. His exertions and the discipline of the Roman troops at length triumphed, and the Nervii were defeated with such immense slaughter, that out of 60,000 fighting men only 500 remained in the state. When the Senate received the dispatches of Cæsar announcing this victory, they decreed a public thanksgiving of fifteen days - a distinction which had never yet been granted to any one.
Third Campaign, B.C. 56. - In the third campaign Cæsar completed the subjugation of Gaul. He conducted in person a naval war against the Veneti, the inhabitants of the modern Brittany, and, by means of his lieutenants, conquered the remaining tribes who still held out. In the later part of the summer Cæsar marched against the Morini and Menapii (in the neighborhood of Calais and Boulogne). Thus all Gaul had been apparently reduced to subjection in three years; but the spirit of the people was yet unbroken, and they only waited for an opportunity to rise against their conquerors.
Fourth Campaign, B.C. 55. - In the following year Cæsar determined to attack the Germans. The Gauls had suffered too much in the last three campaigns to make any farther attempt against the Romans at present; but Cæsar's ambition would not allow him to be idle. Fresh wars must be undertaken to employ his troops in active service. Two German tribes, the Usipetes and the Tenchtheri, had been driven out of their own country by the Suevi, and had crossed the Rhine with the intention of settling in Gaul. This, however, Cæsar was resolved to prevent, and accordingly prepared to attack them. The Germans opened negotiations with him, but, while these were going on, a body of their cavalry defeated Cæsar's Gallic horse. On the next day all the German chiefs came into Cæsar's camp to apologize for what they had done; but Cæsar detained them, and straightway led his troops to attack the enemy. Deprived of their leaders and taken by surprise, the Germans, after a feeble resistance, took to flight, and were almost all destroyed by the Roman cavalry. After this victory Cæsar resolved to cross the Rhine, in order to strike terror into the Germans. In ten days he built a bridge of boats across the river, probably in the neighborhood of Cologne; and after spending eighteen days on the eastern side of the Rhine, and ravaging the country of the Sigambri, he returned to Gaul and broke down the bridge.
Although the greater part of the summer was now gone, Cæsar resolved to invade Britain. His object in undertaking this expedition at such a late period of the year was more to obtain some knowledge of the island from personal observation than with any view to permanent conquest at present. He accordingly took with him only two legions, with which he sailed from the port Itius (probably Witsand, between Calais and Boulogne), and effected a landing somewhere near the South Foreland, after a severe struggle with the natives. Several of the British tribes hereupon sent offers of submission to Cæsar; but, in consequence of the loss of a great part of the Roman fleet a few days afterward, they took up arms again. Being, however, defeated, they again sent offers of submission to Cæsar, who simply demanded double the number of hostages he had originally required, as he was anxious to return to Gaul before the autumnal equinox.
The news of these victories over the Germans and far-distant Britons was received at Rome with the greatest enthusiasm. The Senate voted a public thanksgiving of twenty days, notwithstanding the opposition of Cato, who declared that Cæsar ought to be delivered up to the Usipetes and Tenchtheri, to atone for his treachery in seizing the sacred persons of embassadors.
Fifth Campaign, B.C. 54. - The greater part of Cæsar's fifth campaign was occupied with his second invasion of Britain. He sailed from the port Itius with an army of five legions, and landed, without opposition, at the same place as in the former year. The British states had intrusted the supreme command to Cassivellaunus, a chief whose territories were divided from the maritime states by the River Tamesis (Thames). The Britons bravely opposed the progress of the invaders, but were defeated in a series of engagements. Cæsar crossed the Thames above London, probably in the neighborhood of Kingston, took the town of Cassivellaunus, and conquered great part of the counties of Essex and Middlesex. In consequence of these disasters, Cassivellaunus sued for peace; and after demanding hostages, and settling the tribute which Britain should pay yearly to the Roman people, Cæsar returned to Gaul toward the latter part of the summer. He gained no more by his second invasion of Britain than by his first. He had penetrated, it is true, farther into the country, but had left no garrisons or military establishments behind him, and the people obeyed the Romans as little afterward as they had done before.
In consequence of the great scarcity of corn in Gaul, Cæsar was obliged to divide his forces, and station his legions for the winter in different parts. This seemed to the Gauls a favorable opportunity for recovering their lost independence and destroying their conquerors. The Eburones, a Gallic people between the Meuse and the Rhine, near the modern Tongres, destroyed the detachment under the command of T. Titurius Sabinus and L. Aurunculeius Cotta. They next attacked the camp of Q. Cicero, the brother of the orator, who was stationed among the Nervii. Cicero repulsed the enemy in all their attempts, till he was at length relieved by Cæsar in person, who came to his assistance with two legions as soon as he heard of the dangerous position of his legate. The forces of the enemy, which amounted to 60,000, were defeated by Cæsar, who then joined Cicero, and praised him and his men for the bravery they had shown.
Sixth Campaign, B.C. 63. - In the next year the Gauls again took up arms, and entered into a most formidable conspiracy to recover their independence. The destruction of the Roman troops under Sabinus and Cotta, and the unsettled state of Gaul during the winter, had led Cæsar to apprehend a general rising of the natives; and he had accordingly levied two new legions in Cisalpine Gaul, and obtained one from Pompey, who was remaining in the neighborhood of Rome as Proconsul with the imperium. Being thus at the head of a powerful army, he was able to subdue the tribes that revolted, and soon compelled the Nervii, Senones, Carnutes, Menapii, and Treviri to return to obedience. But as the Treviri had been supported by the Germans, he crossed the Rhine again a little above the spot where he had passed over two years before, and, after receiving the submission of the Ubii, ravaged the country of the Suevi. On his return to Gaul he laid waste the country of the Eburones with fire and sword. At the conclusion of the campaign he prosecuted a strict inquiry into the revolt of the Senones and Carautes, and caused Acco, who had been the chief ringleader in the conspiracy, to be put to death.
Seventh Campaign, B.C. 52. - The unsuccessful issue of last year's revolt had not yet damped the spirits of the Gauls. The execution of Acco had frightened all the chiefs, as every one feared that his turn might come next; the hatred of the Roman yoke was intense; and thus all the materials were ready for a general conflagration. It was first kindled by the Carnutes, and in a short time it spread from district to district till almost the whole of Gaul was in flames. Even the Ædui, who had been hitherto the faithful allies of the Romans, and had assisted them in all their wars, subsequently joined the general revolt. At the head of the insurrection was Vercingetorix, a young man of noble family belonging to the Arverni, and by far the ablest general that Cæsar had yet encountered. Never before had the Gauls been so united: Cæsar's conquests of the last six years seemed to be now entirely lost. The campaign of this year, therefore, was by far the most arduous that Cæsar had yet carried on; but his genius triumphed over every obstacle, and rendered it the most brilliant of all. He concentrated his forces with incredible rapidity, and lost no time in attacking the chief towns in the hands of the enemy. Vellaunodunum (in the country of Château-Landon), Genabum (Orléans), and Noviodunum (Nouan, between Orleans and Bourges), fell into his hands without difficulty. Alarmed at his rapid progress, Vercingetorix persuaded his countrymen to lay waste their country and destroy their towns. This plan was accordingly carried into effect; but, contrary to the wishes of Vercingetorix, Avaricum (Bourges), the chief town of the Bituriges, and a strongly-fortified place, was spared from the general destruction. This town Cæsar accordingly besieged, and, notwithstanding the heroic resistance of the Gauls, it was at length taken, and all the inhabitants, men, women, and children, were indiscriminately butchered.
Cæsar now divided his army into two parts: one division, consisting of four legions, he sent, under the command of T. Labienus, against the Senones and Parisii; the other, comprising six legions, he led in person into the country of the Arverni, and with them laid siege to Gergovia (near Clermont). The revolt of the Ædui shortly afterward compelled him to raise the siege, and inspired the Gauls with fresh courage. Vercingetorix retired to Alesia (Alise, in Burgundy), which was considered impregnable, and resolved to wait for succors from his countrymen. Cæsar immediately laid siege to the place, and drew lines of circumvallation around it. The Romans, however, were in their turn soon surrounded by a vast Gallic army which had assembled to raise the siege. Cæsar's army was thus placed in imminent peril, and on no occasion in his whole life was his military genius so conspicuous. He was between two great armies. Vercingetorix had 70,000 men in Alesia, and the Gallic army without consisted of between 250,000 and 300,000 men. Still he would not raise the siege. He prevented Vercingetorix from breaking through the lines, entirely routed the Gallic army without, and finally compelled Alesia to surrender. Vercingetorix himself fell into his hands. The fall of Alesia was followed by the submission of the Ædui and Arvemi. Cæsar then led his troops into winter quarters. After receiving his dispatches, the Senate voted him a public thanksgiving of twenty days, as in the year B.C. 55.
Eighth Campaign, B.C. 51. - The victories of the preceding year had determined the fate of Gaul; but many states still remained in arms, and entered into fresh conspiracies during the winter. This year was occupied in the reduction of these states, into the particulars of which we need not enter. During the winter Cæsar employed himself in the pacification of Gaul, and, as he already saw that his presence would soon be necessary in Italy, he was anxious to remove all causes for future wars. He accordingly imposed no new taxes, treated the states with honor and respect, and bestowed great presents upon the chiefs. The experience of the last two years had taught the Gauls that they had no hope of contending successfully against Cæsar, and, as he now treated them with mildness, they were the more readily induced to submit patiently to the Roman yoke.