What may perhaps be called Nietzsche’s third period began in 1883 with _Also sprach Zarathustra_, the most extraordinary of all his works, mystical and oracular in form, but not mystical in substance. Zarathustra has only a distant relationship to his prototype Zoroaster, though Nietzsche had a natural sympathy with the symbolism of fire and water, with the reverence for light and purity, which mark the rites associated with the name of the Bactrian prophet; he has here allowed himself to set forth his own ideas and ideals in the free and oracular manner of all ancient scriptures, and is thus enabled to present his visions in a concrete form. _Zarathustra_, for the first and last time, gave scope to the artist within Nietzsche, and with all its extravagance and imperfection it must remain for good or evil his most personal utterance. It was followed by _Jenseits von Gut und Böse_, _Zur Genealogie der Moral_, _Der Fall Wagner_, and _Götzendämmerung_. It is during this period that we trace the growth of the magnification of his own personal mission which finally became a sort of megalomania. (“I have given to men the deepest book they possess, my _Zarathustra_,” he wrote towards the end.) In form the books of this period are sometimes less fragmentary than those of the second period; in substance they are marked by their emphatic, often extravagant, almost reckless insistence on certain views of morality. If in the first period he was an apostle of culture, in the second a freethinker, pronouncing judgment on all things in heaven and earth, he was now exclusively a moralist, or, as he would prefer to say, an immoralist. It was during this period that he worked out his “master morality”--the duty to be strong--in opposition to the “slave morality” of Christianity, with its glorification of weakness and pity, and that he consistently sought to analyse and destroy the traditional conceptions of good and evil on which our current morality rests. The last work which he planned, but never completed, was a re-valuation of all values, _Umwerthung aller Werthe_, which would have been his final indictment of the modern world, and the full statement of his own immoralism and Dionysiac philosophy.