Prince Igor is an opera in a prologue and four acts by the Russian composer Alexander Borodin (see Borodin, Alexander). It was left unfinished at Borodin's death and was completed by two other Russian composers, Nikolai Rimsky-Korsakov and Alexander Glazunov. Borodin himself wrote the libretto (text), which was based on a sketch of an idea by the Russian music critic Vladimir Stasov. Prince Igor received its first performance at St. Petersburg, Russia, on Nov. 4, 1890.