It is worth reflecting that collabarative working is not a new phenomena in music. Four days after Rossini died in 1868 Verdi proposed a requiem mass for the deceased composer, with each individual movement to be composed by a different leading Italian composer of the time. Twelve of the composers who contributed to the ultimate cut and paste job are in the category of forgotten masters (Buzzolla, Bazzini, Pedrotti, Cagnoni, F. Ricci, Nini, Boucheron, Coccia, Gaspari, Platania, L. Rossi and Mabellini), but the thirteenth was Verdi himself. His Libera me was later recycled and incorporated into his own famous Requiem for novelist and poet Alessandro Manzoni.
In typically Italian version the planned performance of the 'Wiki' Messa per Rossini never happened. The extraordinary patchwork lay forgotten until a belated first performance 120 years later, in Parma, in 1988. It was then taken up by choral specialist Helmut Rilling who performed it at his Oregon Bach Festival. He then went on to record it with the Radio-Sinfonierorchester Stuttgart, and that two CD set, which is still in the catalogue, plays as I type this post. (Musically it probably falls into the category of a justly neglected masterpiece).
Of course the Messa per Rossini wasn't a true Wiki work as the composers of the individual movements were identified. Much closer to the Wiki model was the equally fascinating Mont Juic Suite for orchestra. In the 1930's, Benjamin Britten attended a music festival in Barcelona with Lennox Berkeley. He was fascinated by the themes played by the musicians and jotted them down on a scrap of paper. Later Berkeley and Brittem took these scraps, and in true Wiki fashion composed the Mont Juic Suite (Berkeley's Op. 9 and Britten's Op. 12) without identifying the authorship of each of the four movements. But on the liner note of my vinyl Lyrita recording Peter Dickinson says that Berkeley told him Britten wrote the last two movements. So today even the Mont Juic Suite can't claim to be a true Wiki composition.
Let's stay with the collabarative thread. Can anyone add to this post other truly Wiki musical works written by more than one composer, where the authorship of individual movements (or sections) has never been revealed? (Only works by two or more living composers qualify as a Wiki. Cerha's orchestration of the last Act of Berg's Lulu, Sussmayr's completion of Mozart's Requiem, Deryk Cooke's realisation of Mahler 10, or, heavens forbid, Anthony Payne's reconstruction - deconstruction? -
If you enjoyed this post take the overgrown path to A direct line to Britten.