Whether the rest of the sonata would have been in that key is unknown: Fauré never completed it, and in January 1883, the slow movement was published as a stand-alone piece under the title Élégie.
[1] The first performance of the work under its new title was given at the Société Nationale de Musique in December 1883 by the composer and the cellist Jules Loeb to whom the piece is dedicated.
Fauré agreed, and that version was premiered at the Société Nationale in April 1901, with Pablo Casals as a soloist and the composer as conductor.
[4] The orchestral version of the work requires two flutes, two oboes, two clarinets, two bassoons, four horns and strings to accompany the cellist.
The Fauré specialist Jean-Michel Nectoux writes that the Élégie was one of the last works in which the composer allowed himself "such a direct expression of pathos."