Early 20th-century classical music marked a period of experimentation and innovation. Composers like Igor Stravinsky and Arnold Schoenberg challenged traditional forms and harmonies, leading to new styles such as impressionism and expressionism. This era saw the rise of diverse musical movements, including neoclassicism, which sought to revive classical elements in a modern context. The use of dissonance and unconventional scales became more prominent, reflecting the complexities of contemporary life. Composers began to explore new techniques, such as atonality and polytonality, expanding the boundaries of music. This period laid the groundwork for many modern musical developments that followed.