Clarke died at her home in New York at the age of 93.
Although Clarke's output was not large, her work was recognised for its compositional skill and artistic power.
The Rebecca Clarke Society was established in 2000 to promote the study and performance of her music.
She began her studies at the Royal Academy of Music in 1903, but was withdrawn by her father in 1905 after teacher Percy Hilder Miles proposed to her (he later left her his Stradivarius violin in his will).
Some of her works have yet to be published (and many were only recently published); those that were published in her lifetime were largely forgotten after she stopped composing.
Scholarship and interest in her compositions revived in 1976.
The piece shows off the impressionistic musical language Clarke had developed, modeled on the music of Claude Debussy and Ralph Vaughan Williams, that is also apparent in her Viola Sonata.
The harmonies are ethereal and otherworldly; the title is the name of a Greek god, who was especially associated with sleep and dreams.