The first piece was dedicated to Jacques Serres, while the seond was dedicated to Tony Close and Maurice Raskin.
Villa-Lobos's idea was that the entire series of Choros would be played together, starting with the Introduction to Choros, and finishing with the Choros (bis) as an encore. That's a pretty solid chunk of music: about 3 and a half hours, without the two big missing orchestral pieces Choros #13 and #14.
Violin & cello
Published by Max Eschig in Paris. The score is available from Di-Arezzo.
Premiere: 14/03/30, at the Salle Chopin in Paris. Tony Close pllayed the violin and André Asselin the cello, as part of the Festival de Musique Moderne.
There is a single performance in the Villa-Lobos Concerts database (Sept. 2008).