As Hugh MacDonald points out in the New Grove Dictionary of Music and Musicians, "In the years prior to World War I these works were held to be in the vanguard of modernism.
[2] Bülow exposed Strauss to the "music of the future" through his acquaintance with Alexander Ritter, a composer and violinist who had married Richard Wagner's niece and himself had written six symphonic poems similar to those of Franz Liszt.
[3] Before taking up his post in Munich, Strauss spent several weeks touring Italy, during which he took his "first hesitant step" into writing programmatic music by composing sketches for Aus Italien.
He became convinced that an artist's duty included creating "a new form for every new subject" and addressed this problem with Macbeth, the piece which would become his first fully fledged tone poem.
[5] Strauss wrote on a wide range of subjects, some of which had been previously considered unsuitable to be set to music, including literature, legend, philosophy and autobiography.
[1] As Hugh MacDonald points out in the New Grove (1980), "Strauss liked to use a simple but descriptive theme—for instance the three-note motif at the opening of Also sprach Zarathustra, or striding, vigorous arpeggios to represent the manly qualities of his heroes.