As found in the Notitia Dignitatum. Provincial administration reformed and dioceses established by دیوکلتیان, c. 293. Permanent praetorian prefectures established after the death of کنستانتین یکم. Empire permanently partitioned after 395. Exarchates of Ravenna and Africa established after 584. After massive territorial losses in the 7th century, the remaining provinces were superseded by the theme system in c. 640–660, although in آناتولی and parts of Greece they survived under the themes until the early 9th century.