It is hard to approximate a date for the finalization of the Romantic period in music. By the mid-19th century, the underlying concepts of Romantic art had been internalized by most composers, leading to the creation of new forms. Composers as different as Richard Wagner, Johannes Brahms, or Franz Liszt, even as they were confronted in their understanding of music, were part of a search for the expansion of the expressive power of their art. The symphonic poem, the Wagnerian music drama, and many other forms flourished as a response to this quest for structural cohesion in music. The boundaries of tonality and consonance were pushed to the maximum, either as a way of developing the tonal system to a new state, or as a way of breaking free from it. This tendency, coupled with the steady rise of nationalist music, led to the appearance of a number of movements, tendencies, schools, etc., near the end of the 19th century. Some composers chose to return to the simplicity of the Classical forms, some chose to develop the tonal system into new forms, others focused their attention to instrumentation and timbric experimentation. This paved the way for the dissolution of the traditional tonal system and the eventual changes to the very foundation of the musical language. The transition to the next period, around the turn of the century, is also hard to define, as different tendencies progressed in different ways. Some of the iconic composers of the late 19th century period are Anton Bruckner, Gustav Mahler, Pyotr Ilich Tchaikovsky, Giacomo Puccini, Giuseppe Verdi, Johann Strauss, Paul Dukas, The Five (Russian school conformed by Modest Mussorgsky, Nikolai Rimsky-Korsakov and Alexander Borodin among others), and the Impressionists/Symbolist composers (such as Maurice Ravel and Claude Debussy).