This thesis examines the representations of Saint Thérèse of Lisieux produced by the Carmel of Lisieux in the years between the saint’s death in 1897, and that of her sister Céline Martin (Soeur Geneviève de la Sainte-Face) in 1959. It examines the construction of an iconographical foundation for the saint’s cult, the commercial distribution of this iconography, the debate about its authenticity that emerged in the 1920s, and the efforts by the originators of the image to maintain legal control of it. It explores the process of cultural legitimation of these images by the Carmel of Lisieux and, through these, of the cult itself, through a variety of methods, from the articulation of ideas of spiritual and artistic authority, to presence in the mass market, to apologetic, and the use of legislation. The thesis begins by examining the work of the Carmel of Lisieux to visually reshape Thérèse Martin and recast her as a saint through their posthumous representations of her, giving her a new face to fit the existing devotional landscape. Particular emphasis is placed on Céline Martin, as the director of the visual elements of the cult and author of the canonical images of Saint Thérèse, and her personal conceptions of the authentic holy image. The dissemination of the Carmel’s representations of the saint through a programme of popular publications and consumer products is then examined, exploring how the saint was promoted to the Catholic faithful in the religious marketplace, and how the market was used to establish Céline’s images in the economy of popular devotion, giving Thérèse a foothold as a saint who could be believed in. The thesis then turns to the reaction to the Carmel’s visual recasting of Saint Thérèse, examining a group of popular biographies of the saint that appeared in the early twentieth century. Here a body of literature is identified where anxieties over the authentic representation of holy figures are played out, and the emergence of a new paradigm for the representation of the saint is traced. The Carmel is shown to have responded to this with a series of apologetics, where they again articulated the alleged authenticity of their images. Finally, the series of legal cases launched by the convent against producers of unauthorised images of the saint is examined. Here it is shown that the Carmel sought to define Céline Martin as the sole authentic Theresian iconographer through recourse to ideas of religious and artistic authority, using the law of the secular state to make claims to religious authenticity. The first substantial piece of research placing Saint Thérèse in the context of the history of modern French popular religious culture, this thesis provides an insight into the creation of a commercial, devotional cult at the beginning of the twentieth century and the nature of Catholic visual culture in France in the years between the Dreyfus Affair and the Second Vatican Council. In examining the production and dissemination of a cult’s images, the intellectual and legal controversies that followed, and the use of these processes by the originators of the image to legitimate their representations, it also sheds light on prevalent ideas of religious and artistic authenticity in France in the early twentieth century and the search for the ‘true’ face of the saint during that period.