Friedrich Nietzsche. Photograph from the series „Der kranke Nietzsche“ by Hans Olde, between June and August 1899. Original at Goethe- und Schiller-Archiv Weimar, signature GSA 101/37 [in Benders/Oettermann (ed.): Friedrich Nietzsche – Chronik in Bildern und Texten, Hanser / dtv 2000, p. 806/7]