Hermann von der Hardt (1660–1746) was a German Lutheran theologian, church historian, and orientalist who served as professor of Oriental languages at the University of Helmstedt from 1690 and as librarian to Duke Rudolf August of Brunswick-Lüneburg. A pupil of the Pietist August Hermann Francke, he combined wide philological learning with an appetite for documentary history. His best-known work is the six-volume Magnum Oecumenicum Constantiense Concilium (1697–1700), a vast collection of sources on the Council of Constance assembled from manuscripts across German and imperial libraries, which remained a standard reference for conciliar studies well into the modern era. His later allegorical readings of the Old Testament attracted controversy and cost him his theological chair, though he retained his oriental professorship until his death.