
Legio I Gallica was a legion of the Roman Army which was founded in 61 BC in Narbo Martius, Gallia Narbonensis (Narbonne, France) by Secundus Julius Regillus. Throughout 58 BC, the first year of the Gallic Wars, Legio I Gallica remained on garrison duty in Narbo Martius, as Gallia Narbonensis remained on the sidelines of the conflict at the time. However, the Volcae tribe's declaration of war on Rome in 57 BC led to Regillus engaging in a recruitment drive, building up Legio I Gallica's ranks with Roman legionaries and Celtic allies. Legio I Gallica's first battle was the Battle of Narbo Martius, where Legio I Gallica destroyed the Volcae's main army, enabling the legion to advance into Volcae lands and conquer their capital of Tolosa (Toulouse) before pacifying southern Aquitaine.