Schumann wrote that Tristan und Isolde was "the most repugnant thing I have ever seen or heard in all my life". With the passage of time, Tristan became more favourably regarded. In an interview shortly before his death, Giuseppe Verdi said that he "stood in wonder and terror" before Wagner's Tristan. In The Perfect Wagnerite, writer and satirist George Bernard Shaw writes that Tristan was "an astonishingly intense and faithful translation into music of the emotions which accompany the union of a pair of lovers" and described it as "a poem of destruction and death". Richard Strauss, initially dismissive of Tristan, claimed that Wagner's music "would kill a cat and would turn rocks into scrambled eggs from fear of [its] hideous discords." Later, however, Strauss became part of the Bayreuth coterie and writing to Cosima Wagner in 1892 declared: "I have conducted my first Tristan. It was the most wonderful day of my life." In 1935 he wrote to Joseph Gregor, one of his librettists, that Tristan und Isolde was "the end of all romanticism, as it brings into focus the longing of the entire 19th century." The conductor Bruno Walter heard his first Tristan und Isolde in 1889 as a student: Arnold Schoenberg referred to Wagner's technique of shifting chords in Tristan as "phenomena of incredible adaptability and nonindependence roaming, homeless, among the spheres of keys; spies reconnoitering weaknesses; to exploit them in order to create confusion, deserters for whom surrender of their own personality is an end in itself". Friedrich Nietzsche, who in his younger years was one of Wagner's staunchest allies, wrote that, for him, "Tristan and Isolde is the real opus metaphysicum of all art ... insatiable and sweet craving for the secrets of night and death ... it is overpowering in its simple grandeur". In a letter to his friend Erwin Rohde in October 1868, Nietzsche described his reaction to Tristan's prelude: "I simply cannot bring myself to remain critically aloof from this music; every nerve in me is atwitch, and it has been a long time since I had such a lasting sense of ecstasy as with this overture". Even after his break with Wagner, Nietzsche continued to consider Tristan a masterpiece: "Even now I am still in search of a work which exercises such a dangerous fascination, such a spine-tingling and blissful infinity as Tristan – I have sought in vain, in every