Complex sentence: In the twenties and early thirties Crawford Seeger wrote atonal works influenced by Alexander Scriabin, which favored dissonance, post-tonal harmonies and utilized irregular rhythms and meters.
Split into simpler sentences: In the twenties and early thirties, Crawford Seeger wrote atonal works influenced by Alexander Scriabin. These works favored dissonance and post-tonal harmonies; they also utilized irregular rhythms and meters.