Caesar Conquers Gaul

Julius Caesar’s conquest of Gaul reshaped Gallic culture, altered the nature of the Roman Empire, and propelled Caesar toward the domination of Rome.

Summary of Event

Julius Caesar’s conquest of Gaul is among the most significant campaigns in Roman and Western European history. In the Roman context, Caesar’s campaigns fit into the pattern of Roman imperialism. For centuries, commanders ambitious to enhance their political careers by military glory had initiated wars of aggression. For instance, Caesar’s Comenatrii de bello Gallico (51-52 b.c.e.; Commentaries, 1609), released in annual books, were self-promotional press releases. The annexation of Gaul, the largest single acquisition, shifted Rome’s interest from Mediterranean possessions to involvement in northwest Europe and led to campaigns across the Danube and Rhine Rivers (abandoned in 9 c.e.) and then to the conquest of Britain from 43 c.e.
Caesar, Julius
Vatinius, Publius

For Caesar personally, his brilliance as a commander won him glory, immense (and very useful) wealth, the devotion of his soldiers, widespread popularity, and the enmity of those senators who began to fear his ultimate intentions. Having gained a strong military, financial, and political base through the wars, Caesar challenged the Roman establishment in civil war when he marched troops across the Rubicon River in January, 49 b.c.e. When the fighting ceased, Caesar had unprecedented powers as master of Rome—which led directly to his assassination. His career was fundamental in the transition from the failing Republic to the Empire.

Viewed from a different perspective, Caesar’s warfare in the 50’s b.c.e. also altered the culture of the Celtic tribes. Greeks had been settled in southern Gaul and spreading their culture northward since the sixth century b.c.e. Answering an appeal for help from the leading Greek city, Marseilles, Rome conquered the coastal strip in the late 120’s b.c.e. and made it the province of Gallia Narbonensis, named for the colony of Narbo founded in 118 b.c.e. The recent discovery of quantities of Italian wine amphoras prove that Roman merchants were soon operating beyond the provincial boundaries. Commercial activities thus preceded Caesar’s wars by fifty years and may have influenced his policies. Rome applied various labels to this extensive territory: Gallia Transalpina (beyond the Alps, contrasted with Cisalpina, this side of the Alps), Ultima (farthest), Comata (long-haired), and Bracata (trousered).

In 59 b.c.e., the tribune Publius Vatinius sponsored a law that gave Caesar the proconsular governorship of Cisalpine Gaul and Illyricum with three legions for five years. The opportune death of the governor of Narbonensis allowed him to tack on an amendment adding this province and another legion. North of “the Province,” as Narbonensis was often known, lay most of Gaul, a diverse but fertile area between the Rhine River and the Pyrenees and inhabited mostly by Celts. Divided into more than one hundred tribes, the Gauls were unstable politically, with a feuding nobility and rival factions even within tribes.

In the spring of 58 b.c.e. the Helvetii, a group of tribes in western Switzerland, were migrating in search of richer lands and requested the right to pass through the Roman province. Perceiving an opportunity use his newly formed legions and gain military renown, Caesar rushed from Rome to Geneva to block the Helvetii at the Rhone River. Those he did not annihilate he forced to return to their Alpine homes. Later that year, under the pretext of defending Gallic allies, Caesar boldly marched northward to drive back across the Rhine a Germanic chieftain whose aggressions were threatening central Gaul as well as Roman political and presumably economic interests.

Recruiting additional legions in the winter and gaining more Gallic allies, Caesar in 57 b.c.e. ravaged Belgic territory in northern Gaul, overwhelming one tribe after another. When one town resisted a siege, he sold more than fifty thousand of the Belgae into slavery. The following year, building a fleet, Caesar crushed the Veneti who lived along the Atlantic coast. Thus by the end of 56 b.c.e., he had ruthlessly asserted Roman dominance in most of Gaul.

Back at Rome, Caesar’s political enemies charged that he had far exceeded his authority. In 56 b.c.e., however, his political allies obtained the extension of Caesar’s proconsulship for another five years, which encouraged him to press on toward permanent occupation of northern Gaul.

Vercingetorix, mounted, heads toward a meeting with Caesar.

(F. R. Niglutsch)

In 55 b.c.e., two German tribes crossed the Rhine seeking land. When their leaders came to Caesar to negotiate, he detained them and by a surprise attack massacred the Germans, his cavalry hunting down even their women and children. Caesar’s enemy Cato the Younger (95-46 b.c.e.) demanded in the senate at Rome that Caesar be handed over to the Germans to atone for his butchery. Bridging the Rhine, Caesar’s forces briefly invaded Germany, to forestall further Germanic inroads. That same summer, he led two legions in a reconnaissance of Britain, and in the following year, 54 b.c.e., he led a large-scale invasion army across the English Channel, receiving the nominal submission of a British king north of the Thames River. Although Caesar claimed victories, Rome gained no lasting control in Britain or Germany and paid little attention to the island for almost a century. Nevertheless, these expeditions were impressive features in Caesar’s reports to Rome.

Many Gallic tribes refused to accept Roman rule, and Caesar faced several dangerous rebellions in the years 54-52 b.c.e. One crafty chieftain, Ambiorix of the Belgic Eburones, wiped out a Roman legion; Roman merchants as well as Roman supply trains were butchered by the Gauls. Simultaneously, Indutiomarus of the nearby Treveri threatened Rome’s control in the Moselle valley and along the left bank of the Rhine. Enlarging his army to ten legions or about fifty thousand men, Caesar vowed vengeance. Yet a new leader, Vercingetorix, unified a Gallic coalition. His scorched-earth policy forced the Romans to besiege Gallic hill forts. Frustrated, Caesar’s men massacred the inhabitants of several towns. His siege of a stronghold at Gergovia, however, failed miserably, encouraging further desertions by Gauls who had once supported Rome. Only by employing German mercenary cavalry and by dogged discipline and shrewd strategy did Caesar finally outmaneuver and corner Vercingetorix. After a bitter and bloody siege the Gallic hero surrendered. Caesar had him executed after his triumph in 46 b.c.e.


For Caesar, this eight-year campaign brought prominence and increased ambition. His reports to Rome cleverly justified his actions, and his veteran army, intensely loyal to him, enabled him to return to Italy to seize sole power after a civil war. Caesar never had time to do more than begin recovery. Gaul was devastated, perhaps more than half its men of military age slaughtered or enslaved, and its agriculture and towns badly damaged. Scholars are uncertain as to what Caesar’s plans were. By playing on inter- and intratribal enmities, he had won the allegiance of some Gauls. Many Gauls were soon named Julii; they or their ancestors won Roman citizenship through Caesar’s grants. (Most others obtained it from Augustus.) Using demobilized veterans as settlers, Caesar reinforced the colony at Narbo and founded new ones at Baeterrae (Beziers), Arelate (Arles), and probably Noviodunum (Nyon). Evidently following Caesar’s intentions, one of his former officers founded colonies at Raurica (Augst near Basel) on the Rhine and Lugdunum (Lyon) at the confluence of the Rhone and Saône. Because of renewed civil wars, general recuperation only began after 30 b.c.e.

Caesar’s great-nephew and adopted son Octavian, better known as Rome’s first emperor, Augustus (63 b.c.e.-14 c.e.), established the basic administrative structure of the newly conquered lands. Three provinces lay north of Narbonensis: Aquitania, Lugdunensis, and Belgica. Each was divided into administrative units called civitates (cantons), created out of the old tribes. Two military zones, Upper and Lower Germany, ran along the west bank of the Rhine; they became provinces in the early 90’s c.e. Augustus founded several more colonies in Narbonensis, notably Forum Julii (Fréjus) and Arausio (Orange). A network of roads, linked to Narbonensis, radiated from Lugdunum, the chief city of the north. Roman rule soon brought relative peace and order, economic prosperity, and the development of this extensive, agriculturally rich, and prosperous land.

Further Reading

  • Caesar, Julius. The Gallic War. Translated by Carolyn Hammond. New York: Oxford University Press, 1996. One of the earliest significant descriptions of Gallic society. Although Caesar’s point of view is biased, much of his description is substantiated by archaeological evidence.
  • Cunliffe, Barry. The Ancient Celts. New York: Oxford University Press, 1997. Well-illustrated overview of Celtic culture and the changes caused by contact with the Greeks and Romans.
  • Mathison, Ralph, ed. Roman Aristocrats in Barbarian Gaul: Strategies for Survival in an Age of Transition. Austin: University of Texas Press, 1993. Discusses the many ways in which individuals from one of the most sophisticated cities in the ancient world adapted to life in one of the more uncivilized areas of Europe.
  • Woolf, Greg. Becoming Roman. New York: Cambridge University Press, 1998. Studies the cultural history of Gaul between 200 b.c.e. and 300 c.e., describing the process of cultural synthesis that created a unique Gallo-Roman civilization. Illustrations, bibliography, index.

Related Articles in <i>Great Lives from History: Ancient World</i><br />

Julius Caesar; Vercingetorix. Gaul;Caesar’s conquest of