Dmitriy Shostakovich worked on "Boris Godunov" in 1939–1940 on a commission from the Bolshoy Theatre for a new production of the opera. A conflation of the 1869 and 1872 versions had been published by Pavel Lamm and aroused keen interest in the piece. However, it did not erase doubts as to whether Mussorgsky's own orchestration was playable. The invasion of Russia by Nazi Germany prevented this production from taking place, and it was not until 1959 that Shostakovich's version of the score was premiered.