The Fantasy in G major, BWV 572, also known as Piece of orgue à 5, is a piece written by Johann Sebastian Bach for organ presumably in the early Weimar years (by 1712). It is divided into three sections: Très vitement, Grave, Lentement.
The opening section, with one voice, and apparently very similar to a solo instrument to orchestral, is freestyle and toccata, mainly based on arpeggiated figures; the harmonies are fresh and do not deviate never particularly with respect to the reference pitch of G major.
The Grave is an extensive page of polyphony 5 voices, changes in the stern and solemn, which closely resembles, both for thematic material, is by its very structure, the movements of "plein jeu" (organ pleno) of put French seventeenth and eighteenth centuries. In this bracket Bach explores the theme in all possible permutations contrapuntal; from the initial tone of the G major piece modulates gradually toned increasingly distant, ending with a tragic cadence.
This third section is again virtuoso (in it one after another, in fact, of the thirty-sextuplets). It is a page full of color, which at first listen may leave the listener baffled unprepared. The opening line takes up the agreement that closed the "serious", breaking it in arpeggio. The piece unfolds for modulating arpeggios, beneath which the pedal performs the color gamut. After a series of jokes entirely played on a pedal diminante, the Fantasia reaches a serene and powerful conclusion in reference pitch.
In "Attachments" the musical score.