Piano Sonata No. 1 (Enescu)

The Sonata No. 1 for Piano in F-sharp minor, Op. 24, No. 1, is a piano sonata by the Romanian composer George Enescu, completed in 1924.
History.
On 18 July 1912 Enescu completed an Allegro movement for a piano sonata in F-sharp minor, which he played to Herbert Peyser later that summer in connection with an interview. In a heavily reworked form, this would become the first movement of the Sonata, Op. 24, No. 1. However, Enescu set aside this project for twelve years, resuming work again only in 1924. The early version of this movement was only rediscovered in 1993, by the musicologist Clemansa Liliana Firca.
Enescu took up the sonata again in July 1924 in Tețcani, completely rewriting the first movement and adding the other two, completing the work in Sinaia on 27 August 1924. The score was written for and is dedicated to the Swiss pianist Emil Frey, who had been court pianist in Bucharest from 1907 until the outbreak of World War I.
In an interview given shortly after completing the score, Enescu admitted, 
The first performance was given in November 1925 by the composer himself, in a concert that was part of a festival dedicated to his chamber-music works, organized by the Society of Romanian Composers at the Mic Theatre in Bucharest. He also performed the work in Paris for the first time in April 1926, as part of a concert given by the Société Nationale de Musique.
Analysis.
The Sonata is in three movements, whose moderate–fast–slow pattern resembles that of Enescu's Third Symphony.
The first movement is in an extremely free sonata form (though the composer himself declined to characterize it this way). There are two major deviations from the usual sonata design. First, the development begins in the home key of F-sharp minor, while the recapitulation begins in the most distant possible key of C minor, a tritone away from the overall tonic. Second, the sense of arrival of the recapitulation is divided in two by this fact, in that the return of the main theme is separated from the reappearance of its home tonality. The coda of the movement takes on the character of a passacaglia, a feature first noted by the composer Anatol Vieru.
The second movement opens with a gradual accumulation of voices, at first suggesting a fugal exposition with a first answer at the interval of a tritone, but lacking a countersubject. Its burlesque-scherzando character, contrasting with the dark quality of the first movement, resembles those toccatas revived in the music of Debussy and Ravel, or the neoclassical, motoric style adopted in the early twentieth century by composers like Prokofiev. Some other passages resemble the diatonicism of Stravinsky’s Piano Sonata, which was composed slightly later, in the summer and autumn of 1924. The movement does not adhere to any conventional formal scheme and is built economically from a very small number of elements. Although the second theme returns several times, suggesting a rondo form, the recurrences are subject to variations. The most striking of these variants is in a limping 5/4 meter, reminiscent of folk dances such as the "șocâcili" from Banat, the "ghimpele", and "șobolanul" from Oltenia and Muntenia, and the "hodoroaga" from the Ardeal and Moldova regions. Myriam Marbe finds that this movement’s spontaneity and exuberant character suggests, through its pulsating motion, a surging crowd at a public celebration, in a stylized manner similar to the one Stravinsky creates in "Petrushka".
In an interview with Bernard Gavoty broadcast by the French Radio on 25 January 1952, Enescu played part of the finale of this First Piano Sonata as an example of a musical transposition of the atmosphere of the Romanian Plain at night.(
The movement begins evocatively with a single repeated note in an irregular rhythm, whose gentle accents eventually produce the distant signal of a rising minor third, from which the first motif gradually emerges. Hesitant motivic statements separated by long pauses produce a characteristic "spatial poetry" for this movement, which is one of the most striking features of the Enescian style. 
As with the second movement, the form of the finale is difficult to assign to a conventional model. It may be interpreted as a ternary form, or else as a modified sonata-allegro.