(1833-1887) Russian composer. Born in St Petersburg, the illegitimate son of a Russian prince, he became by profession an expert in medical chemistry, but in his spare time devoted himself to writing music. His principal work is the opera Prince Igor, left unfinished; it was completed by Rimsky-Korsakov and Glazunov and includes the Polovtsian Dances. His other works include symphonies, songs, and chamber music, using traditional Russian themes.