Igor Stravinsky (17 June 1882 - 6 April 1971) was a Russian composer, pianist, and conductor in the 20th century. Stravinsky’s compositional career was notable for its diversity. He had a nationalist period where he used Russian folk songs and legends, a neoclassical period where he imitated classical composers that came before him, and a serialist period where Stravinsky used twelve-tone methods.
Stravinsky was known for his ballets, orchestral works, chamber music, and piano compositions. He gained international fame with his compositions for the Ballets Russes: The Firebird, Petrushka, and The Rite of Spring. The Rite of Spring was so unconventional that there was a riot at its premiere, but it also transformed how composers thought about rhythmic structure.
Here is an excerpt from The Rite of Spring. Notice how the accents change. Click on the link under "Suggested Listening" and listen along. Are you having trouble telling where the measure starts? This is exactly how Stravinsky revolutionized rhythmic structure.