The Trois Improvisations for organ were composed in 1911 at the request of Fr.  Joseph Joubert, and published the following year.  The Prelude begins in f minor and ends in the parallel major, but the middle section contains a surprising modulation to c# minor.  The basic unit of construction is a melodic downbeat answered by three eighth-note chords.

Nadia Boulanger (1858-1979)

Prélude from Trois Improvisations, 1912

Recorded on the Lively-Fulcher at St. Patrick's Catholic Church, Washington, D.C.
26 April 2016