As I've said before, Russian music took a while to get established in the classical world. However, the progression of classical music from folk tunes to legitimate classical pieces was catalyzed by five figures in Russian musical history, known in many ways, such as "The Russian Five", or Могучая кучка.
The members of this group include: Mily Balakirev, Cesar Cui, Modest Mussorgsky, Nikolai Rimsky-Korsakov, and Alexander Borodin. Interestingly, these men all had jobs within the military or government, and composing wasn't their primary form of occupation. However, they completely transformed Russian music. Their primary goal was to create a totally "Russian" sound, instead of mimicking other European styles and nuances. Their music was part of a nation-wide Romantic-nationalism revolution that was echoed in other facets of the arts as well.
Their music would help to put Russia on the map of the world of classical music, making new and exciting uses of existing techniques to create a very unique sound. They would also serve to influence the neoclassical and radical musical movements of later composers like Shostakovich, Stravinsky, and Prokofiev.