Gallic Wars

Over eight campaigning seasons, from 58 to 50 BC, Julius Caesar led Roman armies against the peoples of Gaul, roughly modern France, Belgium and Switzerland, and also crossed into Germania and Britain. The conquest, sealed by the siege of Alesia in 52 BC, added all of Gaul to the Roman Republic and gave Caesar the wealth, reputation and loyal army with which he later won a civil war. Most of what is known comes from Caesar's own account, which modern historians read as skilful self-promotion.

The Gauls, whom archaeologists associate with the La Tène culture of the Celts, were wealthy and increasingly urban, and traded widely with Rome. Rome already held Transalpine Gaul in the south, conquered in 121 BC. Caesar, deep in debt after his consulship of 59 BC, used his alliance with Pompey and Crassus to obtain a five-year command over Cisalpine Gaul and Illyricum, to which Transalpine Gaul was added. Historians broadly agree that he went to war chiefly to advance his career and pay his debts, whatever his claims of defending Rome.

In 58 BC the Helvetii, a confederation from the Swiss plateau, began a mass migration westward. Caesar refused them passage through Roman territory, then pursued them anyway and defeated them near Bibracte, sending the survivors home. Caesar later claimed a census in their camp counted 368,000 people; modern estimates are far lower, perhaps 20,000 to 50,000. The same year he defeated Ariovistus, king of the Germanic Suebi, who withdrew across the Rhine.

In 57 BC Caesar turned north against the Belgae. On the river Sambre the Nervii surprised his army while it was building camp and nearly beat it, until reinforcements turned the battle. Afterwards he sold 53,000 Atuatuci into slavery.

In 56 BC Caesar built a fleet to defeat the seafaring Veneti of the Atlantic coast, executed their elders and enslaved the rest, while his officers subdued Normandy and Aquitania. In 55 BC, with his allies Pompey and Crassus holding the consulship in Rome, he sought publicity: he massacred the migrating Usipetes and Tencteri, claiming an implausible 430,000 dead, bridged the Rhine for a brief raid, and made a short landing in Britain. In 54 BC he returned to Britain with five legions, forced the British leader Cassivellaunus to submit and imposed tribute.

After a failed harvest in 54 BC, Gallic tribes rose against the legions wintering among them. The Eburones under Ambiorix tricked a Roman force into leaving its camp and destroyed it, killing both its commanders, and the Nervii besieged Quintus Cicero's camp until Caesar relieved it. In 53 BC Caesar answered with a campaign aimed at civilians, burning villages, seizing livestock and taking prisoners until northern Gaul submitted.

In 52 BC Vercingetorix, king of the Arverni, united an unprecedented coalition and tried to starve the Romans by raiding their supplies. Caesar stormed Avaricum, where he claims 40,000 were killed, but was beaten at Gergovia. Vercingetorix then took refuge in Alesia, where Caesar enclosed both the town and the relief army behind two lines of siege works until the Gauls gave up. Vercingetorix surrendered and was executed in Rome in 46 BC.

Resistance faded in 51 and 50 BC; at Uxellodunum the Romans cut off the defenders' water and then cut off the hands of those who had fought. Caesar withdrew his legions in 50 BC as civil war with Pompey approached. Gaul was formally organised into provinces only under Augustus in 27 BC, and unrest may have lingered as late as AD 70.

Historians now treat the huge Gallic death tolls and tiny Roman losses in Caesar's Commentarii with deep scepticism. The war began nearly five centuries of Roman rule in Gaul, from whose Latin modern French descends, and opened the way to later Roman advances into Germania, checked at the Battle of the Teutoburg Forest.

Our 100 BCE map shows Gaul before the conquest, and our 1 BCE map shows it fully inside Roman territory, covering modern France and Belgium.