Arrondissements of the Bouches-du-Rhône department

There are 4 arrondissements in the Bouches-du-Rhône department. The French departments, and in other countries, are divided into "arrondissements", which may be translated into English as districts (in some cases, as boroughs). The capital of an arrondissement is called a subprefecture.
If the prefecture (capital) of the department is in an arrondissement, that prefecture is the capital of the arrondissement, acting both as a prefecture and as a subprefecture.
Arrondissements are further divided into communes.
The arrondissements of Bouches-du-Rhône are:
History.
Bouches-du-Rhône is one of the original 83 departments created during the French Revolution on 4 March 1790. It was divided in six districts: Tarascon, Apt, Aix, Marseille, Salon and Arles, with Aix as is capital.
In 1800, with the creation of the "arrondissements" in France, the six districts were changed into three "arrondissements": Marseille, Aix and Tarascon. The prefecture was moved from Aix to Marseille.
In 1817, the subprefecture of Tarascon was moved to Arles. The "arrondissement" of Istres was created in 1981.