The opera "Boris Godunov" can either be performed in the first version of 1869, or in the second version of 1874. In fact performances of the opera have often been something of a mixture, as opera directors have often made cuts, or changes to the music or the order of scenes. The composers Nikolai Rimsky-Korsakov and Dmitri Shostakovich have both made new editions of the opera in which they thought they could improve some of Mussorgsky’s harmony or orchestration. For many years it was these editions that were usually performed. Nowadays people realize more and more that Mussorgsky’s harmonies and orchestrations, which were very original for their time, were quite deliberate and very effective. Modern performances therefore often go back to what Mussorgsky originally wrote.