The Viola Concerto, Sz. 120, BB 128 (also known as Concerto for Viola and Orchestra) was one of the last pieces written by Béla Bartók. He began composing his work while living in Saranac Lake, New York, in July 1945. The piece was commissioned by William Primrose, a respected violist who knew that Bartók could provide a challenging piece for him to perform. He said that Bartók should not "feel in any way proscribed by the apparent technical limitations of the instrument"; Bartók, though, was suffering from the terminal stages of leukemia when he began writing the viola concerto and left only sketches at the time of his death.
Primrose asked Bartók to write the concerto in the winter of 1944. There are several letters between them regarding the piece. In one from September 8, 1945, Bartók claims that he is nearly done with it and only has the orchestration to complete. The sketches however show that this was not truly the case. When Bartók died, the piece was finished by his close friend Tibor Serly in 1949. A first revision was made by Bartók’s son Peter and Paul Neubauer in 1995, and it was revised once more by Csaba Erdélyi. The concerto was premiered on December 2, 1949, by the Minneapolis Symphony Orchestra with Antal Doráti conducting and Primrose as violist.
The concerto has three movements, and Bartók states in a letter dated August 5, 1945 that the general concept is, "a serious Allegro, a Scherzo, a (rather short) slow movement, and a finale beginning Allegretto and developing the tempo to an Allegro molto. Each movement, or at least 3 of them will, [be] preceded by a (short) recurring introduction (mostly solo for the viola), a kind of ritornello." (The aforementioned idea of a thematic introduction to each movement was also used in Bartók's String Quartet no. 6 Sz. 114.) The first movement is in a loose sonata form. The slow second movement is significantly shorter, and closes with a very short scherzo movement that is an attacca right into the third movement. The time stamps, as seen in Bartók’s manuscript, state that the first movement should be 10’20", the second 5’10" and the third 4’45".