The diocese was established after the reforms of Diocletian and Constantine I in ca. 314 AD. In 407, the Vandals and their allies invaded Gaul, devastating the region until they departed for the Iberian peninsula in 409. The Visigoths were brought in as foederati to aid the Romans against them, and in 418 emperor Honorius allowed them to settle in Aquitania around Toulouse. Although nominally Roman subjects, the Goths were practically independent, a fact which was formally recognized by the Western Empire in 475, just one year before its end. In 462 Ricimer ceded them also the province of Narbonensis Prima, while the Goths proceeded to occupy the remaining provinces east of the Rhone in 477. Henceforth, the lands that had comprised the diocese of the Seven Provinces were part of the Visigothic Kingdom. Aquitania was soon lost to the Franks, with only the southern coastal strip (Septimania) retained by the Goths.
Provincial administration reformed by Diocletian, ca. 293. Praetorian Prefectures established after the death of Constantine I. Empire permanently partitioned after 395. Exarchates of Ravenna and Africa established after 584. Provinces replaced by Theme system, ca. 680.
* affected (boundaries modified/abolished/renamed) by Justinian's administrative reorganization in 534-536 † re-established after reconquest by the Eastern Empire in 534, as the separate praetorian prefecture of Africa
