Carl Reinecke's Sonata in E minor is based on the German romantic tale found in the 19th century novel Undine. Written by Friedrich de la Motte Fouque in 1811, the novel made a great impact on it's readers and it is no surprise that the story became the inspiration for music, ballets, plays, art, and poetry.
The tale centers around the water spirit Undine, daughter of the King of the Sea. Sea maidens are lovelier and longer-lived than their mortal counterparts, living peacefully in crystal palaces deep beneath the waves. The one thing the water spirits lack, and Undine longs for, is an immortal soul. The only way a water spirit can obtain an immortal soul is through uniting in love with a mortal man.