Rusalka is an opera by Antonín Dvořák. The Czech libretto was written by the poet Jaroslav Kvapi (1868-1950) based on the fairy tales of Karel Jaromír Erben and Božena Němcová; a Rusalka is a water sprite of Slavic mythology, usually inhabiting a lake or river.
Song to the Moon
Help him remember his dreams of me,
tell him I'm waiting for him,
make him remember me when he awakens.
O Moon, do not falter!