The initial emotional symptoms of Nietzsche's breakdown, as evidenced in the letters he sent to his friends in the few days of lucidity remaining to him, bear many similarities to the ecstatic writings of religious mystics insofar as they proclaim his identification with the godhead. These letters remain the best evidence available for Nietzsche's own opinion on the nature of his breakdown. Nietzsche's letters describe his experience as a radical breakthrough in which he rejoices, rather than laments. Most Nietzsche commentators find the issue of Nietzsche's breakdown and "insanity" irrelevant to his work as a philosopher, for the tenability of arguments and ideas are more important than the author. There are some, however, including Georges Bataille, who insist that Nietzsche's mental breakdown be considered.
In the latter part of the 1880s, Nietzsche’s health worsened, and in the midst of an amazing flourish of intellectual activity which produced On the Genealogy of Morality, Twilight of the Idols, The Anti-Christ, and several other works (including preparation for what was intended to be his magnum opus, a work that editors later titled Will to Power ) Nietzsche suffered a complete mental and physical breakdown. The famed moment at which Nietzsche is said to have succumbed irrevocably to his ailments occurred January 3, 1889 in Turin (Torino) Italy, reportedly outside Nietzsche’s apartment in the Piazza Carlos Alberto while embracing a horse being flogged by its owner.