Which composer introduced new harmonic styles in the twentieth century?

One prominent composer who introduced new harmonic styles in the twentieth century is Igor Stravinsky. His innovative use of dissonance, complex rhythms, and unconventional scales, particularly in works like "The Rite of Spring," revolutionized musical language. Additionally, composers like Arnold Schoenberg with his twelve-tone technique expanded harmonic possibilities, paving the way for atonality and new approaches to composition. These innovations significantly influenced the direction of modern music.