20th-century classical music
In Russia, which became the Soviet Union after the 1917 Revolution, composers were not allowed to be experimental. It was difficult for them because they had to please the politicians who told them that their music should reflect “Socialist realism” (meaning the workers’ struggle against capitalism). The great tradition of writing symphonies continued with Sergei Prokofiev (who spent some time in exile) and Shostakovich (who remained in the Soviet Union).