Marie d’Oignies (c. 1177–1213) was a mystic from the diocese of Liège, located in the Southern Low Countries. Her widely disseminated Vita Mariae Oigniacensis (1215)—the story of her life and visions—was written by Jacques de Vitry (d. 1240), but her spiritual example and close connections ensured that Marie d’Oignies would become the director of her own narrative and legacy. She ranks prominently among spiritual elites within the early semi-religious movements, which find their roots in the twelfth century. The writings about her are some of the earliest attestations of this religious innovation, not only defending, but also to a certain extent authorizing the semi-religious lifestyle. As a model of devotion, Marie d’Oignies proved to be an influential figure of religious authority, particularly within the sphere of female lay piety.