Due to a lack of sources documenting everyday teaching practices, historians engaging with the use of the optical lantern in education have traditionally focused on the top-down implementation of the medium. This contribution presents a rare case study of how the medium was actually used by focusing on a lesson on the saint Joan of Arc that was taught by means of the optical lantern at a Catholic school for girls. This analysis is enabled by the preservation of an exceptionally rich collection of lantern slides and related materials, including a notebook with the text that was probably used during the projection of the images. These sources show that the teacher who was in charge of the lesson went to great lengths to combine various images and text fragments with each other, creating a unique narrative that corresponded to her Catholic worldview and goals.