On December 9, 1905, the French Third Republic ratified the Law on the Separation of the Churches and the State. The law, touted by contemporaries as advantageous to the productive, modern country, ended the ancient relationship between the French state and the Catholic Church and severed collaboration between the government and all religious institutions. The ratification of the law was considered by anticlerical contemporaries an emancipatory measure that would liberate the French citizenry from the illogical belief-systems of the Catholic Church. However, despite the changes wrought by these secularization laws, France’s outward ties to Christianity continued to feature prominently in public discussions after 1905, particularly regarding France’s Islamic colonies. In fact, early twentieth-century newspapers, government documents, and academic research regularly highlighted the religious dichotomy between the “Christian” French and the “Muslim” inhabitants of North Africa, particularly those of Morocco: the Islamic Kingdom across the Mediterranean Sea that had become the focal point of French imperial aspirations in the early twentieth century. Thus, even as anticlericalists lauded France’s new secular status, they—along with their Catholic counterparts—concurrently drew upon the centuries-old religious rivalry that set the “French Christians” against the “Muslims” of North Africa. Herein lies an interesting paradox: after the Law of Separation, at a moment when France’s connections to Christianity should have been downplayed within mainstream newspapers, the halls of government, and the French public sphere more generally, both Catholics and secularists in the press, government, and in various areas of colonial knowledge production frequently assigned the label “Christian” to describe the French writ large vis-à-vis the label “Muslim,” a term applied generally to the Moroccans. This dissertation endeavors to explain the epistemological origins of this trend by illuminating the complex role that Christianity played in the construction of French views towards Islam—and, subsequently, French colonial policy—in the nineteenth and early twentieth centuries.