Legio XIII was levied by Julius Caesar in 57 BC, before marching against the Belgae, in one of his early interventions in intra-Gallic conflicts. During the Gallic Wars (58–51 BC), Legio XIII was present at the Battle against the Nervians, the Siege of Gergovia, and while not specifically mentioned in the sources, it is reasonable to assume that Legio XIII was also present for the Battle of Alesia.