Complex sentence: At fifteen he moved to Moscow, then capital of the Soviet Union, where he later entered the Moscow State Conservatory, graduating with honors in Music Composition and Piano, in 1989 and 1990, respectively.
Split into simpler sentences: At fifteen he moved to Moscow, then capital of the Soviet Union. He later entered the Moscow State Conservatory, graduating with honors in Music Composition and Piano, in 1989 and 1990, respectively.