>>17798376
They did not revolt. Justinian declared war on them illegally, not even respecting Roman laws, without any reason since the Foederati reges in Spain, Italy and Carthage were recognized by treaties and supported by local patricians. He did not respect the treaties his predecessor made with the Vandals, Visigoths and Ostrogoths.

Since Justinian broke his treaties, he became an illegal tyrant and the reges from the West were fully authorized to rule until a legit emperor was restored. This happened at the winter of year 800 when Charlemagne, from the Regnum Francorum was declared emperor by the bishop of Rome, ie, the pope, head of the Christendom.