Catholicism was the state religion of France during the Atlantic age and the activities of missionary orders of priests, friars, and nuns were an integral part of the colonizing process. French missionaries came to Louisiana in the 18th century and Senegal in the 19th century in an attempt to convert Africans and Native Americans to Catholicism. The missionaries saw themselves as agents of salvation for the people they proselytized and stressed the spiritual nature of their enterprises in Louisiana and Senegal. Colonial authorities, on the other hand, saw Catholicism as a useful tool in the assimilation and control of non-French colonial populations. Historians who have studied the missionaries have found that they had both positive and negative effects on the people they evangelized and converted.
In Louisiana, Capuchin friars and Jesuit priests arrived in the first years of the 18th century to take charge of ministering to French colonists and converting Indians and enslaved Africans. In 1727 they were joined by the Ursuline nuns, whose specialty became the evangelization of enslaved women and girls. Sacramental records reveal that the nuns were more successful than their male counterparts in recruiting enslaved Africans to Catholicism. Neither group had much luck in the conversion of Native Americans.
The missionary effort in Senegal reached its height a century after the activity in New Orleans had reached its peak. There, the French colonial administration invited three French religious orders to send missionaries to Senegal. The main objective of these missionary undertakings by the Sisters of Saint-Joseph of Cluny, the Ploërmel Brothers, and the Sisters of the Immaculate Conception, was to convert the majority Muslim population to Catholicism. They supplied the major source of French language education and Catholic religious instruction to the colonized Senegalese until the 20th century, when a secular education system was established.