Final answer:
In the Modernist movement, composers embraced dissonance as an aesthetic principle and created alternative systems of composition. This period marked a departure from traditional tonal harmony and embraced innovative approaches to music.
Step-by-step explanation:
In the Modernist movement, composers embraced dissonance as an aesthetic principle and created alternative systems of composition. This period, which took place during the late 19th and early 20th centuries, marked a departure from traditional tonal harmony and embraced innovative approaches to music. Composers like Arnold Schoenberg introduced atonality and experimented with a twelve-tone scale, challenging established musical conventions. This era saw a rejection of the Romantic era's emphasis on structure and a move towards more subjective and individualistic artistic expressions.