 In June 1794 Humboldt settled in Jena at a time when the city and its University became the center of German idealist philosophy and the Romantic movement and entertained contacts with the philosopher Fichte and with Friedrich and August Wilhelm Schlegel. He assumed the role of philosophical adviser and critical collaborator of Goethe and especially Schiller. Through his discerning criticism he furthered the production of some of their important works, for example Schiller’s Briefe über die Ästhetische Erziehung des Menschen of 1795 (Letters on the Aesthetic Education of Man), and his philosophical poems as well as Goethe’s epic Herrmann und Dorothea and his novel Wilhelm Meister. For Schiller’s newly created journal, Die Horen, he authored two important contributions, “Ueber den Geschlechts-Unterschied” (“On Sexual Difference”) where he formulated a gender theory on the basis of contemporary natural philosophy and “Ueber männliche und weibliche Form” (“On the Male and Female Form”) where he extended this theory into the realm of the arts and culture (1794, 1795, GS Vol 1: 311–34, 335–69). While in Jena he joined forces with his brother Alexander and Goethe and together the three men engaged in a study of the evolving new discipline of comparative anatomy at the University. Humboldt used the insights he had gained from this study to create a comprehensive blueprint for a future comparative anthropology (“Plan einer vergleichenden Anthropologie” (1797, GS Vol 1: 377–410). But only years later when he attempted to lay the foundation for his newly conceived discipline of general and comparative linguistics, he would return to it and rework his ideas.