Monna Vanna; Monna Vanna- an unfinished opera by Sergei Rachmaninoff (1873-1943) after a play by Maurice Maeterlinck. . Had Rachmaninoff proceeded to a complete operatic setting, such a work could not have been produced in European countries which were signatories to copyright laws that covered the work of Maeterlinck. This opera could only have been produced in countries, such as Russia, which at the time were not signatories to European copyright law. Ultimately, Rachmaninoff abandoned further work on this opera and never wrote a complete setting.