In the 410s, they sacked Rome. The Legion of Smoke heard rumours that they were assisted by real witches, called Tenctrama. After the defeat, accepting their own weakness and lack of discipline, the Roman Emperor gave Visigoths and other germanic tribes space to settle and entered into trade agreements with them.
When Attila the Hun marched into Gaul with his army, Visigoths chose to fight with the Romans against him. In 451, during the Battle of the Catalaunian Plains, Romans led by Flavius Aetius fought alongside Visigoths, led first by King Theodoric and then, after a Tenctrama witch killed him, by his son Thorismund. The alliance has also provided Romans with the assistance of Tenctrama, whom Romans themselves rejected on religious grounds. However, Flavius Aetius had no illusions about the strength of their alliance and considered a betrayal a real possibility.
After the Thirteenth Doctor defeated the Tenctrama and prevented them from turning all soldiers on both sides into dead fuel for their necrotic life cycle, Thorismund left with his army to ensure his position of the king of Visigoths against his multiple brothers. At that time, the Visigoth lands lay to the south of Gaul. (PROSE: Combat Magicks)