While the Jewish and Classical sources of Freud's thought have been thoroughly researched, less interest has been focused on his relations with German Romanticism. However, the biological theories of nineteenth-century Germany were steeped in the Philosophy of Nature, which even persisted within the materialistic school of Helmholtz that succeeded it. This source re-emerges in Freud through his medical mentors and through Fliess, Fechner and Lipps, latter-day German Romantics.

Freud was to make use of the Romantic conceptions of dreams, the unconscious and repression, instincts and their origins, excitation, bisexuality, jokes and aesthetics, the broadening of the ego through education, interest in animal magnetism, and so on, while profoundly transforming them. Romanticism is also a feature of Freud's style and a characteristic of the culture hero embodied in his work.