Structural Forms of Symphonic Poetry

Since the symphonic poem was born in the Romantic period (including the Romantic School and the National School), then in the pre-development of the symphonic poem, the work because of the reference to the sonata form (such as Smetana's "My Fatherland" and Borodin's "On the Steppes of Central Asia"). But with the end of the era, Impressionism and Expressionism introduced symphonic poetry into the range of atonal music, Debussy in the symphonic sketch of the importance of harmony, abandoning the traditional major and minor keys and sonata form, Schoenberg even more atonal symphonic poetry orchestrated short and concise.