Borodin worked on his opera Prince Igor on and off from 1869 to the end of his life. Though his chemistry career and other projects often demanded his attention, he regularly returned to Prince Igor, his magnum opus. 1
Prince Igor remained unfinished at Borodin’s death. Rimsky-Korsakov acted as his musical executor and completed the opera with help from Alexander Glazunov.2
Research and reconstruction are ongoing to discover Borodin’s original vision for Prince Igor. Soviet musicologist Pavel Lamm did research suggesting that there is much unpublished Prince Igor music by Borodin which Rimsky-Korsakov left out of the published score.3
Borodin himself wrote the libretto, from a scenario by V.V. Stasov, based on the c. 12th Century epic poem Slovo o polku Igoreve (‘The Lay of the Host of Igor’).4
Story: the plot concerns Igor’s doomed military campaign against the Polovtsians (a Russian name for a Turkic-speaking people group), during which he almost loses both his princedom and his life.5