On the 3rd of January 1889, Nietzsche suffered a mental collapse. Two policemen approached him after he caused a public disturbance in the streets of Turin.
What happened remains unknown, but an often-repeated tale from shortly after his death states that Nietzsche witnessed the flogging of a horse at the other end of the Piazza Carlo Alberto, ran to the horse, threw his arms up around its neck to protect it, and then collapsed to the ground.
In the following few days, Nietzsche sent short writings—known as the Wahnzettel (“Madness Letters”)—to a number of friends including Cosima Wagner and Jacob Burckhardt. Most of them were signed “Dionysos”, though some were also signed “der Gekreuzigte” meaning “the crucified one”.
To his former colleague Burckhardt, Nietzsche wrote: “I have had Caiaphas put in fetters. Also, last year I was crucified by the German doctors in a very drawn-out manner.
Wilhelm, Bismarck, and all anti-Semites abolished.”Additionally, he commanded the German emperor to go to Rome to be shot and summoned the European powers to take military action against Germany.
Nietzsche’s mental illness was originally diagnosed as tertiary syphilis, in accordance with a prevailing medical paradigm of the time. Although most commentators regard his breakdown as unrelated to his philosophy, Georges Bataille dropped dark hints (“‘Man incarnate’ must also go mad”) and René Girard’s postmortem psychoanalysis posits a worshipful rivalry with Richard Wagner.
Nietzsche had previously written, “all superior men who were irresistibly drawn to throw off the yoke of any kind of morality and to frame new laws had, if they were not actually mad, no alternative but to make themselves or pretend to be mad” (Daybreak, 14).
The diagnosis of syphilis has since been challenged and a diagnosis of “manic-depressive illness with periodic psychosis followed by vascular dementia” was put forward by Cybulska prior to Schain’s study. Leonard Sax suggested the slow growth of a right-sided retro-orbital meningioma as an explanation of Nietzsche’s dementia; Orth and Trimble postulated frontotemporal dementia while other researchers have proposed a hereditary stroke disorder called CADASIL. Poisoning by mercury, a treatment for syphilis at the time of Nietzsche’s death,has also been suggested.
In 1898 and 1899 Nietzsche suffered at least two strokes. This partially paralyzed him, leaving him unable to speak or walk. He likely suffered from clinical hemiparesis/hemiplegia on the left side of his body by 1899.
After contracting pneumonia in mid-August 1900, he had another stroke during the night of 24–25 August and died at about noon on the 25th of August.
Elisabeth Nietzsche had him buried beside his father at the church in Röcken bei Lützen. His friend and secretary Gast gave his funeral oration, proclaiming: “Holy be your name to all future generations!
Warning* There is no graphic imagery in the following video but some may find it disturbing.