The Whole North Into Gaul

[Flavivs Aetivs]

I'd have to argue that there were several factors that play into that. First of all, Thorismund besieged Arles in 452, and Aetius did not have the military forces to break the siege. Aetius was likely waiting for an attempt to catch the Goths off-guard and hopefully break them in an ambush, but that's besides the point. After Ferreolus persuaded the Visigoths to break the siege, Theodoric II was unhappy that his brother had broken the treaty with their Roman allies, and assassinated Thorismund. He then quickly established friendly relations with Aetius. One of Theodoric's younger brothers was made an honorary magister militum, and a contingent of Visigoths under him was dispatched to destroy the Bacaudae of Tyriassionis, who had taken all of Tarraconensis.