A Study On The Structural Generation Of The "Overlapping" Sonata Form Of The Sibelius Tone Poem En Saga

En Saga,composed in 1893,was the first tone poem composed by Sibelius.En Saga is considered by Sibelius to be one of his most impressive works.Although Sibelius used En Saga as the title of the work,he never explained the exact meaning of the title.The interpretation of the Kalevala is more in line with the characteristics of the historical period in which Sibelius composed.The En Saga forms a special sonata form at the end of its structure generation process,in which the presentation and development sections are not presented sequentially as in a conventional sonata form,but the main part of the presentation section is followed by the development center I of the development section,in which the main part material is the core,and the presentation of the secondary theme is followed by the development center II of the development section,in which the secondary material is the core.The overall feature of staggered and overlapping presentation of the presenting part and the expanding part is the"overlapping"sonata style.The main theme in the recapitulation section returns to the main key of C minor,but in the presentation section it is presented in the key of its reduplicated name,~#c minor,which is another outstanding feature of the genesis of En Saga.There are two sub-themes in En Saga,and the sub-themes are presented in ~bE major in the presentation section and returned to the key of c minor in the recapitulation section,reflecting the typical cadential principle,which is the decisive condition for the generation of the sonata form;the relationship between the main theme and the first sub-themes has a thematic distortion,and the relationship between the second sub-themes has an unfolding variation.These are another distinctive feature of the En Saga.