This article analyzes the histories of religions of Louis de Bonald, Antoine Fabre d'Olivet, Pierre-Simon Ballanche, and Ferdinand d'Eckstein. Rather than offer yet another definition of Romanticism, it seeks to establish a framework by which to render intelligible a set of early nineteenth-century French histories of religions that have been largely ignored in the history of the study of religion. It establishes their mutual affinity by demonstrating that they are built on the common structural elements of an essentialist ontology, an epistemology that eludes Kantian pessimism, and a philosophy of history that depicts development as the unfolding of a preexistent essence according to an a priori pattern. Consequent upon these structural elements we may identify five characteristics of French Romantic histories of religions: organic developmentalism; reductionism; hermeneutic of harmonies; apologetic intent; and reconceptualization of Christian doctrine. Romantic histories of religions, as syntheses of traditional faith and historical-mindedness, are at once a chapter in the history of the study of religion and in the history of religious thought.