 In the later division of the Roman Empire under the Emperor Diocletian, the eastern part of Mauretania Caesariensis, from Saldae to the river Ampsaga, was erected into a new province, and called "Mauretania Sitifensis" from the inland town of Setifis (Setif in modern Algeria).At the time of Constantine the Great, Mauretania Sitifensis was assigned to the administrative Diocese of Africa, in the praetorian prefecture of Italy.The new province had a huge economic development in the IV century, until the conquest by the Vandals.