How did Igor Stravinsky challenge traditional rhythm and harmony in early 20th-century music?

Igor Stravinsky revolutionized 20th-century music by rejecting traditional Germanic thematic development in favor of a sculptural approach, where musical structures were built cumulatively through the repetition and variation of "sound objects".1

Rhythmic Innovation

Stravinsky challenged traditional rhythmic norms by moving away from the subdivision of regular groups. Instead, he treated rhythm as a cumulative process, adding together varied groups of sound objects. His work, most notably The Rite of Spring, introduced:1
* Metric Imbalances: He utilized asymmetrical metrical patterns that broke down the tradition of symmetrical phrasing.21
* Constantly Changing Rhythms: His compositions featured shifting, percussive momentum that challenged audiences accustomed to regular pulses.231

Harmonic Innovation

Stravinsky’s approach to harmony was empirical and experimental, often prioritizing coloristic value over traditional functional resolution. His techniques included:41
* Drastic Dissonance: He frequently employed dissonant harmonies, sometimes by layering two unrelated diatonic chords simultaneously.241
* Isolation of Chords: Even in his Neoclassical period, he used classical harmonies in isolation, allowing them to move freely without adhering to their traditional functional roles.41
* Polytonality: He experimented with the simultaneous use of multiple keys, as seen in works like Three Pieces for String Quartet, which suggests four keys at once.5