Late Roman Republic, Julius Caesar, Caesar’s Reduction of Gaul (58-56 BC): Helvetii

Helvetii (Switzerland); Arar River and Bibracte

Caesar was pretty much broke. Conquest of a new province would allow him both to enrich himself and to display his military ability. In happened that there were two convenient pretexts for launching a campaign in Gaul: there was the matter of Rome’s failure to support their allies the Aedui against Ariovistus; and in spring 58 BC the Helvetii, a tribe in modern-day Switzerland, living under pressure from the German tribes, asked to pass through the lands of the Sequani and Aedui and enter that of the Santones on the Atlantic coast.

Other governors could have acceded, but Caesar delayed the Helvetians’ progress with negotiations, while he fortified the Rhone below Geneva against them, forcing them to make their way down the north bank of the river. Caesar, who had summoned the three legions from Aquileia to join him and raised two more (XI and XII) bringing his total to six, followed the Helvetii northwest towards central Gaul.

He came up to the Helvetii at the Arar (=Saone) above Lyon (central-east), where three quarters of the enemy force had already crossed the river. Caesar surprised and destroyed the rest on the east (left) bank. The Helvetii still had two hundred and fifty thousand warriors and were heading down the Loire River. Finding that his rations were growing short, Caesar ceased the pursuit and moved away towards Bibracte (central-east), where there was plenty of corn. The Helvetii, interpreting this as a withdrawal, turned and offered battle.

Caesar withdrew to a hill and awaited their attack. The Romans had the advantage of height and their volleys of javelins soon took effect. A general charge was ordered and legionaries drove the Helvetii before them. The survivors crossed a stream and gained the opposing ridge. At this point, the Helvetian rearguard, a force of fifteen thousand men, who had only now arrived on the battlefield, launched an attack on the exposed flank of the legions. Caesar was forced to fight on two fronts, but Roman discipline prevailed. Barely a third of Helvetians survived, and Caesar ordered them to return to their homes and rebuild their villages.