From the Wikipedia page [1]
Constantine is a former French département in Algeria which existed between 1848 and 1962. The area of the former department, centered on the city of Constantine, is also referred to as Constantinois (Arabic: قسنطينة Qusanṭīnah).
Considered a French province, Algeria was departmentalised on 9 December 1848. Three civil zones (départements) replaced the three beyliks into which the Ottoman former rulers had divided the territory. The principal town of the eastern département, also called Constantine, became the prefecture of the eponymous département. The two other Algerian departments were Oran in the west and Alger in the centre.
On 7 August 1955 the eastern extremity of the département of Constantine was split off and became the separate département of Bône. Less than two years later, in May 1957, population increases triggered the creation of the stand-alone departments of Sétif and of Batna from the western and southern portions of the département of Constantine.
The much truncated coastal département of Constantine now covered just 19,899 km², and was home to a population of 1,208,355. It was redivided into seven arrondissements: these were Aïn Beïda, Aïn M'lila, Collo, Djidjelli, El-Milia, Mila and, as before, Philippeville.
The 1957 departmental reorganisation was marked by a change in the "suffix" number appearing on automobile license plates and in other places that used the same code. Until 1957 Constantine was department number "93": after 1957 the much diminished département of Constantine became department number "9D". (In 1968, under a law enacted in 1964, the number "93" would be reallocated to a new département comprising the northern and north-eastern suburbs of Paris.)
The département of Constantine remained in existence after the independence of Algeria and became Constantine Province in 1968.