Summary of Bellum Gallicum Book 1

Reading Caesar's works in English can be a little dull, and sometimes can be downright difficult. This overview is meant to serve as a thorough, but hopefully approachable, summary of Book 1.

The gray highlighted passages are the Latin readings. Names will be in bold the first time they are mentioned. Major events to know will also be highlighted.

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The ethnic groups of Gaul during Caesar's conquests.

Book 1 of de Bello Gallico recalls the events of 58 BCE, and begins by giving a geographical account of Gaul's various subdivisions and some basic ethnographic description of the various peoples, especially in regards to military strength. The HELVETII, a small ethnic group living within the Celtic subsection of Gaul, encouraged by a local noble ORGETORIX, plan a mass migration. Orgetorix's migration plan includes his overthrow of the state and the establishment of monarchy. He enlists CASTICUS OF THE SEQUANI TRIBE and DUMNORIX OF THE AEDUI TRIBE to help out, and the three plan to turn Gaul into their personal kingdom. The plot leaks into the Helvetii aristocracy, and Orgetorix is put on trial. He incites violence and dies under questionable circumstances during the rioting. His death does not undo the migration plan, however, and the Helvetii plan to march south through Allobroges territory.

The ALLOBROGES, on the fringes of Roman territory, ask for aid. Caesar rushes to their capital, Geneva, raises troops, burns the bridge giving the Helvetii access to Geneva. The Helvetii send ambassadors (legati) to Caesar asking for the right to pass through Roman territory. He stalls for time by asking a few weeks to deliberate.

Caesar uses the time he asked the Helvetii for to build a defensive barriet. When the Helvetii return to get Caesar's answer, the wall he's built in the meantime makes it clear that he will deny them entry. The Helvetii try to force their way through, but Caesar's defenses hold. The Helvetii are forced to turn northwest and enter Gaul through Sequani territory. The narrow paths through Sequani territory are too easily defended against a migration, so the Helvetii send an ambassador to Dumnorix. Dumnorix is not king of the Sequani, but he is influential and is the son-in-law of the now dead Orgetorix. Dumnorix agrees to help the Helvetii and gets them permission to pass through. Caesar makes it clear that Dumnorix does this for his own power rather than out of any sense of kindness. Dumnorix will always be an antagonist to Caesar's plans.

When Caesar finds out that the Helvetii are moving north, he decides that Helvetii migration will put hostile forces too close to the southern parts of Gaul under Roman control (specifically, the Tolosates state). Caesar leaves Labienus in charge of the Geneva fortifications, and takes 25,000 men--5 legions worth--to stop the Helvetii migration. The Centrones, Graioceli, and Caturiges tribes all tried to stop Caesar, but he blasts through them on the way to the Helvetii. Caesar marches from the border of the Roman province of Cisalpine Gaul to the far side of the Rhone in seven days. By that time, the Aedui have send ambassadors to Caesar requesting help against the Helvetii migration.

Caesar gets further news that the Helvetii are crossing the Arar River (the Soane today). Caesar performs a night attack on the final quarter of Helvetii troops who have not yet crossed the river. This final quarter of the Helvetii was actually a sub-tribe called the Tigurini. This same tribe actually killed Caesar's grandfather-in-law during a battle, and Caesar notes this act of revenge as a particular sign of divine favor. The Tigurini were carrying much of the Helvetii's baggage, meaning that the Helvetii have lost lots of supplies as well as troops. This battle of the Arar River is the first major battle of the Gallic War, and is a victory for Caesar.

Caesar's victory complete, Caesar orders a bridge built by his military architects, then crosses the Arar with his army in a single day. The Helvetii are shocked by his speed (it took the Helvetii 3 weeks), and thus the Helvetii send Divico, who happened to be the commander at the battle where the Tigurini defeated the Romans so many years ago.

The negotiations go roughly like this: Divico says that if Caesar makes peace, he can tell the Helvetii what territory in Gaul to occupy. He then reminds Caesar that he personally has defeated Roman armies before, so taking this offer would be wise. Caesar refuses and demands hostages. Divico refuses this counteroffer, and the talks end.

The Helvetii forces move to a new camp ground, and the Roman allied cavalry follow. The Roman cavalry get too close and a skirmish breaks out that the Roman cavalry loses. The Helvetii use the initiative to try and get the Romans to make an attack on ground advantageous to the Helvetii. Caesar doesn't fall for it. The Romans follow the Helvetii forces closely for about fifteen days, while Caesar asks for food supplies from the Aedui.

With a different latitude and a different climate, Gallic grain supplies are lower than Caesar would like--he can't take grain from the fields, and the stores of Grain the Aedui have are low. Caesar had sent ships with grain to supply the Romans, but he was too far inland following the Helvetii to make that grain a reliable source. The Aedui promise Caesar the grain will be ready any day, but when Caesar realizes this is just a stall tactic, he summons the chieftains--including Divitiacus, brother of Dumnorix, and Liscus, who holds the title of Vergobretus, or chief magistrate, among the Aedui. Caesar scolds the chieftains for their dishonesty. Liscus replies that there is a powerful faction of private Gallic citizens who view the Romans as the greatest threat to Gallic liberty. Liscus had kept this information from Caesar out of fear of reprisal were his report found out.

Caesar correctly assumed the head of this private faction was Dumnorix. In a later, private meeting, Liscus confirms this. Dumnorix has amassed a following of clients through massive monetary gifts, and has been the tax collector for the region. Dumnorix married off his mother to a leader among the Bituriges tribe to the west to secure that alliance, Dumnorix's own wife is a Helvetii, and he has given his other female relatives away in marriage to secure a pan-Gallic alliance. Caesar also finds out that Dumnorix is angry at his brother Divitiacus' influence with the Romans, and worries that Divitiacus will get all the power in any future Roman governance of Gaul. Finally, Liscus says that the cavalry skirmish was lost because Dumnorix retreated early in the fight, and his sudden flight left the rest of the cavalry convinced the fight was a lost cause. Dumnorix was also responsible for the Helvetii moving through Sequani territory, and had exchanged hostages, all without the permission of the Aedui government.

Caesar believed that either he should punish Dumnorix or that the Aedui state should do it. The only problem was Divitiacus--an honest ally to the Romans, a genuinely good leader for his own people, and the personal favors Divitacus has done for Caesar--would be upset if the Romans went after a member of his family. In order to avoid a political fallout, Caesar summoned Divitiacus for a tete-a-tete (one on one). At first, they speak through regular translators, but eventually, Caesar talks with him through Procillus (also called Troucillus), the Roman chief of Gaul and a personal friend and confidant of Caesar. Caesar lays out to Divitiacus the accusations against his brother Dumnorix, then asks if Dumnorix can be punished without Divitiacus being offended.

Divitiacus weeps, asking Dumnorix be spared from harsh punishments despite the truth of the accusations. Even though Dumnorix had betrayed Divitiacus himself, Dumnorix was still his brother and was popular among the Aedui. Caesar summons Dumnorix, explains the charges against him, and explains that he pardoned Dumnorix because of his brother's request. After advising Dumnorix to avoid any suspicious activity in the future, Caesar appoints spies to follow Dumnorix's movements and activities.

News comes to Caesar that same day; the Helvetii have camped at the foot of a mountain eight miles away. Caesar orders Labienus to move 10,000 infantry under the cover of night up the mountainside above the enemy camp. Caesar sends the cavalry and leads out his own forces of infantry just before dawn. Considius, a veteran of Sulla and Crassus' armies, is sent ahead with scouts.

By morning, the Romans hold a position uphill less than two miles from the enemy without the enemy knowing the Romans were there. Considius runs and says the Helvetii hold the position where Caesar had wanted Labienus' troops to move next to prepare for battle. So Caesar moves to another hill nearby and lines up for battle. Caesar learns through spies that Considius' intelligence was wrong--Labienus' advance forces had taken the mountain. Caesar, relieved, moves again to follow the Helvetii camp.

Caesar's men were almost out of food by this time, so he needed to resupply in order to maintain the offensive against the Helvetii. The well-supplied Aeduan town of Bibracte was nearby, so Caesar changes direction and advances to the city. Roman deserters from the Gallic cavalry led by Aemilius inform the Helvetii of a sudden movement by the Romans. The Helvetii misinterpret Caesar's move as a sudden, fearful retreat. The Helvetii move out against Caesar's men and attack the rear of Caesar's men. This starts the battle of Bibracte.

Caesar takes a position on a nearby hill and sends cavalry to attack the Helvetii. He lines up four legions near him, two legions with the auxiliaries at the peak of the mountain, and all the baggage behind them. The Helvetii dropped off their baggage behind them and attacked the Roman cavalry. The Roman cavalry pull back, the Helvetii form a phalanx formation, and begin to march up the hill towards the four legions.

Caesar moves all the cavalry away so his troops don't think about reinforcements protecting their retreat, encourages the men, and orders his men to throw their pila. The pila cause enough shields to become unusable that the Helvetii abandon their phalanx and attack with their secondary swords. After some fighting, the Helvetii begin to wear out and retreat to a mountain a mile off. The Romans pursued and began to surround the troops when the allies of the Helvetii, the Boii and Tulingi, sprung into action. The Boii and Tulingi, 15,000 troops strong, were responsible for protecting the rear of the Helvetii forces and began to attack the Romans from the side. The Helvetii, seeing their allies attack, charge back upon the Romans. The Romans, facing attacks from the front by the Helvetii and from the rear by the Boii and Tulingi, split into two: the front two lines of troops face the Helvetii, while the third line faces the side attack.

The Romans were almost surrounded, but the Helvetii had been forced to a retreat to this nearby mountain--the fight here went on for hours. The Helvetii forces began to retreat further up the mountain or head back to their baggage. As night approached, the Romans were able to push towards the baggage train. The Helvetii set up their wagons as a barricade for their archers, javelin throwers, and slingers. Eventually, the Romans pushed their way to the baggage and took it, capturing two of the children of Orgetorix.

130,000 of the enemy had successfully escaped the battle and marched several days northeast to the territory of the Lingones. The Romans stayed put for several days to recover, but Caesar sent messages to the Lingones stating that any support the Helvetii forces would be seen as an act of war. After three days, the Romans pursued, but the Helvetii were ready to surrender and sent ambassadors to surrender.

The Helvetii made a big scene of submission to Caesar prior to negotiations starting. Caesar demanded hostages, weapons surrendered, and the return of any runaway slaves. One group of Helvetii, called the Verbigene, fled across to Germany during the night rather than surrender their weapons.

When Caesar found out, he ordered local inhabitants to find and capture the Verbigene and return them. They would all be killed, but the other Helvetii would be allowed to surrender under the previously given terms. The Helvetii, Tulingi, and Latobrigi were ordered to return to their original territories, and ordered the Allobroges to provide supplies of food and construction materials to rebuild the burned-out Helvetii homelands. This would ensure the Germans would not invade and create an even larger threat to Roman forces. The Aedui requested the Boii to be incorporated into their own territory to provide new troops and citizens, to which Caesar agreed. This set of terms officially ends the battle of Bibracte, and the end of the Helvetii as a fighting force.

Caesar found the census records of the Helvetii, written in the Greek alphabet. There were 368,000 Helvetii people, and a military force of 92,000. Caesar demanded a new census of those who returned home, and the number of Helvetii was 110,000--a loss of 258,000, or a decrease of 70% of the population.

The Helvetii threat ended, legati from all over Gaul came to congratulate Caesar and to thank him for eliminating this threat on their people. The Gauls also remind Caesar that this had been of a great benefit to the Romans as well, as they had pacified the lands near their province. The Gauls requested Caesar allow a pan-Gallic council be formed to meet with him and make some requests. He allowed it.

The Pan-Gallic council met and dismissed, but some leaders wanted to meet with Caesar in private. When they met, they threw themselves at Caesar's feet. After stating that they were afraid of disclosing some information for fear of reprisal, Divitiacus the Aeduan explained:

"There were two major Gallic factions: the Aedui and the Arverni. The two factions were neck-and-neck for years, but the Arverni and Sequani hired the Germans as mercenaries to get the upper hand. The Germans started to flood in and wiped out most of the Aedui, but it backfired. Our chieftains are forced to be sent as hostages. The Sequani have it even worse than we do, though, because Ariovistus, king of the Germans, evicted the Sequani from their homeland, causing mass migrations and encouraging larger numbers of Germans to cross. After Ariovistus won a battle at Magetobria against the Gauls, he's been a cruel tyrant. The Romans must help. If Ariovistus found out the Gauls approached Caesar about this matter, Ariovistus would punish all his hostages, so they requested Caesar approach Ariovistus himself."

The leaders around him Divitiacus were distraught, and the Sequani even refused to cry out out of fear of their relatives being tortured by Ariovistus in reprisal.

Caesar assured that he would reach out to Ariovistus and dismissed the leaders. Caesar was deeply concerned about both the apperance of the Aedui, who were on friendly terms of the Roman senate, being mistreated by the Germans, and equally worried about Germans invading into territory so near to Roman provinces. On top of this, Caesar felt the arrogance of Ariovistus deserved to be checked.

So Caesar began a correspondence with Ariovistus that went like this:

Caesar: I'd like to discuss affairs of state that are important to both of us.

Ariovistus: If I needed to talk, I'd have messaged you. Besides, I'm not going into Roman-occupied Gaul without an army. By the way, why are you worried about things happening in my territory?

Caesar: You were once named a king and friend by the Roman Senate, so the invitation of a Roman governor to talk shouldn't be casually refused, nor should a king consider that friends have no interest in how kings run their kingdoms. But here is what I demand: stop bringing Germans across the Rhine, release hostages from the Aedui and Sequani, and do not declare war on the Aedui. In exchange, the Roman people will keep approving of his behavior. But if you refuse, I will fulfill my legal obligation to protect the Aedui from mistreatment.

Ariovistus: I conquered this place according to the rights of war, just like how the Romans often do, and those who conquer have the right to govern however they want. I also don't dictate policy to the Romans on their conquered lands, so why you have the right to do so to me is unclear. The Aedui attempted to fight, meaning they understood the consequences of failure. If the Aedui pay me the tributes they agreed to, I won't fight them. If they stop, the fact they are Roman allies won't help them. As far as your threats, no one has ever fought me without falling to ruin. You, Caesar, can join the list of those I've defeated with my army of Germans, men so tough they haven't stood under a roof for fourteen years, and so well-trained that they were invincible.

The Aedui and Treviri arrived simultaneously with the last message of Ariovistus. The Harudes, a German tribe, were attacking the Aedui, and Ariovistus refused to stop the attacks; meanwhile, the Treviri were fighting off a massive invasion of the Suevi led by the brothers Nasuas and Cimberius. Caesar decided to gather troops and marched out to Ariovistus.

After three days, Caesar finds that Ariovistus was marching towards the Sequani capital of Vesontio. Caesar tought this should not happen because of Vesontio's ability to produce military supplies and its natural fortifications. Caesar rushed out and established a garrison at the city.

After delaying a few days in the city, Caesar's troops began to hear rumors that the Germans were monstrous fighters, and a near mutiny occurred, worsened by some officers who had little prior battle experience. Caesar summoned a council that included all the centurions and shamed them all. He criticized their insubordinate questioning of his commands. He reminded them that it was Caesar himself during his consulship that had named Ariovistus a friend of the Roman people, and it was not at all clear that Ariovistus would refuse the terms offered after some time for consideration passed. But even if Ariovistus did refuse, the Romans had defeated the Cimbri, a large German tribe, under Gaius Marius. The rebellious slave Spartacus had some troops escape to the Germans, but the Romans had defeated Spartacus. The Helvetii had defeated the Germans in multiple skirmishes over the years, and the Romans had just defeated the Helvetii. Every force that had given Ariovistus difficulty had been defeated by the Romans with relative ease. Ariovistus' success was based on the fact he didn't offer a battle for months, but suddenly rushed into Gaul without warning. Those who feared the terrain or the grain supply was putting the Romans at a disadvantage doubted Caesar's abilities and were insubordinate. Caesar was confident enough in his success that he was going to depart the next day. He knew the 10th legion would follow him anywhere, and if no one else followed, Caesar would not be slowed by their shame.

All Caesar's officers were roused to action by his speech. The 10th legion thanked him for the particular honors given. Caesar had Divitiacus scout the road ahead and reveal a route that would be difficult to ambush. Caesar left out with his men before daylight.

After a march of seven days, Caesar was closing in on Ariovistus's position. When Ariovistus became aware of Caesar's approach, he sent legati to arrange a meeting. Caesar had some hopes that Ariovistus was going to be sensible, but Ariovistus suddenly demanded that Caesar should not bring any foot-soldiers to the council, meaning Caesar's bodyguard would have to be made of Gallic cavalry. Caesar ordered his cavalry to dismount and put members of his favorite legion, the 10th, on horseback. The scene caused one soldier to joke that Caesar had promoted the 10th legion to the rank of equites (knights, AKA an elite class or Roman citizen). This is also the cause of the 10th legion to gain the nickname of the mounted tenth legion.

A large mound surrounded by a wide plain was the site for the meeting between Ariovistus and Caesar. The cavalry were held 200 feet back from the meeting, and Ariovistus demanded each leader bring ten men to the center. Caesar again agreed to the demand. The broad strokes of the summit went like this:

Caesar: The senate has named you king and friend. These gifts were usually given for personal favors to a senator, but I gave them to you out of my own kindness. The Aedui and Romans have been long-standing allies, and the Aedui have had dominance over Gaul going back to pre-history. The Romans aim to increase the prosperity of their allies, not to see them diminish. I make the same demands as before: do not make war on the Aedui or their allies, return hostages, and do not bring over any more Germans from across the Rhine.

Ariovistus: I did not cross the Rhine on my own whims. I was invited. I would not have left if I didn't expect great rewards, and the Gauls had given me and my people settlements. Hostages were exchanged willingly. I took the prizes conquerors get when they conquer people.

The Gauls attacked me, not the other way around. I defeated all the Gallic nations in one battle. If they want to try again, I'm ready for them, but if they want peace, they should pay a tribute. That's not an unfair request, and they have willingly paid it until now.

My friendship with the Romans should boost my power, not check it--that's why I wanted the title. But if the Romans are going to stop the tribute payments from the Gauls, I'll renounce the title of friend no less eagerly than I tried to gain it.

As far as leading troops into Gaul, I wanted to secure my own borders, not expand them. I did not attack the Gauls with those forced; I fought them off.

I was also here before you. So what do you want, Caesar? Why are you in my kingdom? This is my province, and you have your own. You would consider me in the wrong for attacking your province, so I consider your actions in the wrong.

As far as the Aedui being allies by the Senate, I know the Aedui did not help the Romans fight the Allobroges nor gave them any form of help, nor did you help them when the Aedui had been fighting the Sequani. I can't help but be suspicious that your 'friendship' with Gaul is more about conquering them than helping them.

If I killed you right now, I'd be in the right as king of this realm, but I know for a fact that more than a few senators would gladly name me a friend of the Senate. So go away, leave Gaul to me. I'll end what wars you want ended, and you won't have to bother.

Caesar: I cannot ignore this situation, and Roman custom demands I stick to our deserving allies. Gaul doesn't belong to you. Q. Fabius Maximus defeated the Arverni and Ruteni but later pardoned them without punishment centuries ago. If we consider historical arguments, the Romans ruling Gaul was just. If the decree of the Senate matters, then Gaul should be free, as it had been conquered by Rome and was allowed to use its own laws.

While all this conversation took place, the cavalry of Ariovistus kept sneaking closer to the mound and throwing stones and darts at the Romans. Caesar ended his speech and withdrew his men, ordering that no attack should occur until he gave word. Caesar thought he would win the fight, but he didn't want it to appear as if he had fallen for a trap laid by Ariovistus. The word spread that Ariovistus was arrogant and treacherous, making Caesar's troops all the more eager for a fight.

Two days later, Ariovistus asked for another conference, but Caesar did not see a reason to go himself. He sent Procillus, a non-Roman officer and translator, as his legatus. Mettius, who at one point had been a guest of Ariovistus, also was sent. When they approached, Ariovistus accused them of acting as spies and arrested them.

Ariovistus moved his camp within six miles, then two miles away from the Roman camp. Caesar lined up for battle five days in a row, but Ariovistus did not engage. He kept his troops in camp, and only sent out his cavalry to skirmish with the Romans. Caesar mentions the horsemen had swift infantry troops who followed behind and rushed out to protect their man if he fell off his horse. If needed, they could hold on to the horses manes and run alongside the horse.

Caesar moved two legions into a smaller camp within half a mile of Ariovistus' army so he would not be cut off from supplies, but even then Ariovistus did not line up his troops for battle. Caesar led his troops out for battle once again, and a skirmish broke out, but Ariovistus did not send out his whole army and eventually led them back into camp. Finally, Caesar found out the reason for Ariovistus' reluctance: the German women had read the omens, and had declared that the Germans would not conquer unless they waited for a new moon.

The next day, Caesar drew up his auxiliaries in front of the enemy in front of his smaller camp. He used the auxiliaries because he had far fewer Roman troops compared to the number of the enemy army. He drew up the army into three lines and advanced at the enemy camp. The Germans unwillingly engaged, surrounding themselves with their chariots and wagons so there would be no escape. They placed the women on the chariots and wagons to urge on the German troops. This set the stage for the battle of Vesontio.

Caesar put each legion under a legatus and a quaestor to demonstrate their bravery to that group of soldiers. Caesar himself led the right wing because that was where the enemy was strongest. The Romans attacked, and the Germans responded with a rush forward so fast that the pila were not thrown as was customary. The Germans formed a phalanx while the Romans fought with swords. Many Romans jumped on the phalanx, ripping away shields and spears to make a hole in the formation.

The left wing of the enemy fled, the right wing was still fighting hard. Publius Crassus, a cavalry commander and son of the triumvir Crassus, sent troops to support the right wing. This reinforcement crushed the spirit of the Germans, who fled in an unorganized retreat all the way back to the Rhine about fifty miles away. Some tried to swim across the river if they couldn't find a boat. Ariovistus himself escaped on a boat back across the Rhine. Caesar's cavalry slaughtered anyone caught on the west side of the river. Ariovistus' two wives--one Gallic and the other German--were killed in the flight. Procillus was found by Roman forces, and he later reported that there had been three acts of divination to decide whether he should be immediately killed, and through good fortune he was spared. Mettius, the other ambassador, was also saved. The battle of Sevontio was a crushing victory for the Romans, and was the last time Ariovistus appeared in any known historical account.

The Suvevi had begun to return home when the Ubii, another German tribe, ambushed them and slaughtered the vast majority of them. Caesar moved his forces into Sequani territory for the winter early, feeling that two successful wars was enough for one campaign season. Caesar put Labienus in charge of the winter quarters before returning back to his province to fulfill his duties as proconsul, part judge and part governor, in Cisalpine Gaul.