Around the end of the 5th century, the majority of the dioceses of the Western Roman Empire ceased to exist, following the establishment of the Barbarian kingdoms. There is no evidence that the Franks and Burgundians maintained the Roman provincial system; the Visigoths and Vandals did maintain the provinces (governed by "rectores" or "iudices"), but not the dioceses or prefectures. In Italia, Odoacer and then the Ostrogothic kings, particularly Theoderic, basically retained the Roman provincial system, including the Praetorian Prefecture of Italia and the two vicariates of Italia Annonaria and Italia Suburbicaria, as well as the various provinces that they contained. When Theoderic conquered Provence in 508, he also re-established a Diocese of the Gauls, which was promoted to the rank of Prefecture with a capital at Arelate two years later. This Praetorian Prefecture was abolished in 536, during the reign of Vitiges, after the cession of Provence to the Franks. The rationale behind Odoacer and Theoderic's maintenance of the Roman provincial system was that they were officially viceroys of the Roman emperor in Constantinople, for whom Italia nominally continued to form part of the Roman empire. The civilian offices, including the vicars, praesides, and Praetorian Prefects, continued to be filled with Roman citizens, while Barbarians without citizenship were barred from holding them. According to Cassiodorus, however, the authority of the "vicarius urbis Romae" was diminished: in the 4th century, he no longer controlled the ten provinces of Italia Suburbicaria, but only the land within forty miles of the City of Rome.