April. Köselitz officially returns to the Nietzsche Archive as the editor of Nietzsche's correspondence. With the death of his mother, he is able to move from Annaberg to Weimar (address Lisztsraße 22, moving to Luisenstraße 13/II in August). From this time on, he uses the pseudonym for himself that FN coined: "Peter Gast."
Friedrich Nietzsche dies on 25 August 1900.
There has been much debate about what caused FN's madness and eventual death. Most agree that it was syphilis. In the February 14, 1999, issue of The New York Times Book Review, Dr. Archinto P. Anzil, Professor Emeritus of Neuropathology at the State University of New York-Downstate Medical Center in Brooklyn, N.Y. offered this opinion: "Friedrich Nietzsche suffered from a tertiary form of neurosyphilis, namely, from general paresis of the insane or dementia paralytica. This is an inflammation of the brain tissue, i.e., an encephalitis caused by or at least etiologically related to the microbial agent of syphilis. A typical and early manifestation of dementia paralytica is the development of paranoid ideas, usually notions of grandeur: patients think of themselves as being one of the paramount historical figures of their time or of times past. Characteristically, Nietzsche, imbued as he was in classic pre-Christian antiquity, thought he was the god Dionysus. As for Carl Nietzsche, the philosopher's father, he died of a stroke, a very common condition that as a rule has nothing to do with syphilis."
September 3: Köselitz marries Elise Wagner of Leipzig.
September 13: Overbeck visits Köselitz briefly in Weimar. In December he receives the first volume of FN's correspondence as edited by Köselitz. He gives up the idea of Köselitz being the inheritor of his Nietzsche materials, deciding instead to bequeath it to the University of Basel.