or by contracting cholera intentionally; in the New Grove Dictionary of Music, Roland John Wiley wrote: "the polemics over Tchaikovsky's death have reached an impasse … . As for illness, problems of evidence offer little hope of satisfactory resolution: the state of diagnosis; the confusion of witnesses; disregard of long-term effects of smoking and alcohol. We do not know how Tchaikovsky died. We may never find out." Music Antecedents and influences Of Tchaikovsky's Western predecessors, Robert Schumann stands out as an influence in formal structure, harmonic practices and piano writing, according to Brown and musicologist Roland John Wiley. Boris Asafyev comments that Schumann left his mark on Tchaikovsky not just as a formal influence but also as an example of musical dramaturgy and self-expression. Leon Botstein claims the music of Franz Liszt and Richard Wagner also left their imprints on Tchaikovsky's orchestral style. The late-Romantic trend for writing orchestral suites, begun by Franz Lachner, Jules Massenet, and Joachim Raff after the rediscovery of Bach's works in that genre, may have influenced Tchaikovsky to try his own hand at them. His teacher Anton Rubinstein's opera The Demon became a model for the final tableau of Eugene Onegin. So did Léo Delibes' ballets Coppélia and Sylvia for The Sleeping Beauty and Georges Bizet's opera Carmen (a work Tchaikovsky admired tremendously) for The Queen of Spades. Otherwise, it was to composers of the past that Tchaikovsky turned—Beethoven, whose music he respected; Mozart, whose music he loved; Glinka, whose opera A Life for the Tsar made an indelible impression on him as a child and whose scoring he studied assiduously; and Adolphe Adam, whose ballet Giselle was a favorite of his from his student days and whose score he consulted while working on The Sleeping Beauty. Beethoven's string quartets may have influenced Tchaikovsky's attempts in that medium. Other composers whose work interested Tchaikovsky included Hector Berlioz, Felix Mendelssohn, Giacomo Meyerbeer, Gioachino Rossini, Giuseppe Verdi, Vincenzo Bellini, Carl Maria von Weber and Henry Litolff. Creative range Tchaikovsky displayed a wide stylistic and emotional range, from light salon works to grand symphonies. Some of his works, such as the Variations on a Rococo Theme, employ a "Classical" form reminiscent of 18th-century composers such as Mozart (his favorite composer). Other compositions, such as his Little Russian symphony and his opera Vakula the Smith, flirt with musical practices more akin to those of the 'Five', especially in their