Battle of Bibracte

The Battle of Bibracte in 58 BC was the first set-piece victory of Caesar's Gallic War. The Helvetii, some 368,000 souls by Caesar's own contested count, had left their homeland for a migration southwest; Caesar blocked them at the Rhône, shadowed their march, and offered battle near Bibracte when they turned on his rear guard. His legions held the slope of a hill against the Helvetian assault, then counterattacked and broke them; the defeated host surrendered or fled east, and Caesar forced the survivors back to their old lands. The win opened the long conquest of Gaul and gave his veterans a loyalty that would follow him to the Rubicon. Caesar's legions had shadowed the Helvetian column for two weeks after barring its passage at Geneva, refusing battle until his supplies were secure and his legionaries were led across the Saône. When the migrants turned on his rearguard under the quaestor, the legions formed on a slope near Bibracte in the land of the Aedui, threw down the Helvetian assault from the high ground, and then charged downhill to break the host. The remnants surrendered to the Aedui and were resettled in their old country, whose vacant lands the Boii were later granted.