Between 1918 and 1939, France rebuilt the nearly 4,000 Catholic churches of the Western Front that had been destroyed during the First World War. This thesis presents a cultural history of that process. While it examines technical and financial aspects of reconstruction, the thesis is primarily interested in how Catholics understood the cultural significance of church reconstruction through the shifting and porous contexts of war and peace during the interwar years. It considers how church reconstruction operated at multiple levels: material, conceptual, rhetorical, and ritual. In tracing the evolution of reconstruction efforts across the period—from wartime discourses about reconstruction to the final church reconstructions of the late 1930s—this thesis argues for a trajectory of radicalization. It finds that church reconstruction was initially part of a program for pragmatic post-war reconstruction and modest religious revival in France, but later became the centerpiece of a Catholic crusade for social conquest of domestic political opponents. The history of the reconstruction crusade reveals the persistence of wartime mentalities in French Catholic culture of the interwar period. This thesis ultimately presents the post-war reconstruction of Catholic heritage sites as a fraught process and suggests that conflict can paradoxically persist through the reconstruction of religious sites previously implicated in conflict.