[1] 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 split into a new province, and called Mauretania Sitifensis named after the inland town of Setifis (Setif in modern Algeria).

[2] At the time of Constantine the Great, Mauretania Sitifensis was assigned to the administrative Diocese of Africa, under the Praetorian prefecture of Italy.

In this province, the Christian denomination known as Donatism challenged the Roman Church (which was the main local religion after Constantine), while Setifis was a center of Mithraism.

Indeed, the emperor Maurice in that year created the office of "Exarch", which combined the supreme civil authority of a praetorian prefect and the military authority of a magister militum, and enjoyed considerable autonomy from Constantinople.

Mauretania Sitifensis initially had an area of 17800 square miles and had a good agriculture (cereals, etc..), that was exported through the port of Saldae.