Since the Bouches-du-Rhône department is one of the most populous and diverse departments, it has long been the scene of particularly fierce political battles. The development of the Marseille-Fos Port, the relationship maintained between France and its colonial empire, the industry around coal mining in Provence, and significant immigration, especially coming from Italy, from the end the nineteenth century and during the period between the two wars are all factors that led to the emergence of a large and militant working class. From the late nineteenth century, the socialist movement gained influence, such as by in 1881 by the election of the first socialist member of France, Clovis Hugues. Rural areas, and particularly in the region of Aix have tended to favor the influence of right-wing parties, including monarchists and Catholics at the beginning of the French Third Republic. The interwar period and the time of the Popular Front marked the beginning of the dominance of the left in the department, first with the election of the SFIO.