 Beyond the issue of reason’s autonomy or priority, another central issue for Natorp is reason’s history; again, this is a concern typical of the Marburg School generally; one of its peculiarities is the quasi-Hegelian insistence upon the integration of the systematic and historical moments of philosophy. Cohen wrote major essays on Plato (Cohen 1866, 1878), and Natorp’s early work concentrated on what the Marburgers considered ancient and early modern anticipations of the critical philosophy. Then there is Natorp’s magnum opus, Platos Ideenlehre of 1903, in which he simultaneously develops a “critical” interpretation of the theory of forms and an argument for the order of the dialogues, all conceived as an “Introduction to Idealism” (cf. Laks 1994, 2003).