The Tenth legion was among the oldest in the imperial Roman army. It was previously known as “Equestris,” meaning mounted because Caesar once used these legionaries as cavalry. Being one of the twenty-eight original Augustan Legions, it was inherited by Caesar in Spain in 61 B.C. The tenth Legion played a crucial role in the Gallic wars and fought with Caesar in virtually every battle. It was said to be the reason of Caesars military success thus being his favorite legion.
The legion consisted of 10 cohorts. The basic designation of the 10 cohorts was the same throughout all the Legions. They were arranged in battle so that the strongest and weakest units would be mixed throughout the formation maximizing moral and effectiveness. This legion remained faithful to Caesar in the civil war against Pompey, including the battles of Pharsalus and Munda. Later Caesar disbanded the legion as he gave the veterans farmlands. In time Equestris was re-constituted as Legio X Gemina, the twin legion. It was one of the four legions that was used by Caesar for the invasion of Gaul. This legion was also given the symbol of a bull.
It started out with the encounter of a German leader, Ariovistus, who was the leader of Suebi. He is described as “rex Germanorum” by Caesar meaning “King of Germans.” He was known to have encountered eastern Gallic territory prior to Caesar. Ariovistus believed Caesar’s presence in eastern Gaul was a violation, which led to Caesar preparing for the “impending conflict.” Due to the proximity of the Germans, Caesar’s legions were too frightened to face the enemy’s ferocity. The only legion eager to join their beloved commander Caesar was the Tenth Legion.