Formerly an independent kingdom, and later a client state of Rome, it was annexed into the Empire formally during the reign of Claudius and divided into two provinces about 42 AD.

A third province, named Mauretania Sitifensis, was later split off from the eastern portion during the reign of Diocletian in 293 AD.

Mauretania Caesariensis included eight colonies founded by the Emperor Augustus: Cartennae, Gunugus, Igilgili, Rusguniae, Rusazus, Saldae, Zuccabar, Tubusuctu; two by the Emperor Claudius: Caesarea in Mauretania, formerly the capital of Juba II, who gave it this name in honour of his patron Augustus, and Oppidum Novum; one by the Emperor Nerva: Setifis; and in later times, Arsenaria, Bida, Siga, Aquae Calidae, Quiza Xenitana, Rusucurru, Auzia, Gilva, Icosium and Tipasa in all 21 well-known colonies, besides several municipia and oppida Latina.

[2] At the time of Diocletian and Constantine the Great, both Sitifensis and Caesariensis were assigned to the administrative Diocese of Africa, under the Praetorian prefecture of Italy.

[citation needed] The principal exports from Caesariensis were purple dyes and valuable woods; and the Amazigh or Mauri were highly regarded by the Romans as soldiers, especially light cavalry.