For the Boston Symphony Orchestra's 50th anniversary, he commissioned Copland's "Ode", Prokofiev's Symphony No. 4 (which Prokofiev later revised), Paul Hindemith's "Concert Music for Strings and Brass", and Stravinsky's "Symphony of Psalms", as well as works by Albert Roussel and Howard Hanson. In 1922, Koussevitzky commissioned Maurice Ravel's arrangement of Modest Mussorgsky's 1874 suite for piano, "Pictures at an Exhibition", which was premiered on 19 October that year and quickly became the most famous and celebrated orchestration of the work. Koussevitzky held the rights to this version for many years.