Wikipedia
(German for The King's Children) is a stage work by Engelbert Humperdinck that exists in two versions: as a melodrama and as an opera or more precisely a Märchenoper. The libretto was written by Ernst Rosmer (pen name of Else Bernstein-Porges), adapted from her play of the same name.
In 1894, Heinrich Porges asked Humperdinck to write incidental music for his daughter Else's play. Humperdinck was interested in making the story into an opera but since Else Bernstein-Porges initially refused, he opted for the play to be staged as a melodrama – that is with spoken dialog taking place along with an instrumental backdrop. (The work also included operatic arias and choruses, as well as unaccompanied dialog.)
In the melodramatic passages, Humperdinck designed an innovative hybrid notation that called for a text delivery somewhere between singing and speech. With this notation, the singer was expected to deliver a substantial portion of the text with approximate pitched melodies. This version was first staged at the Munich Hoftheater, with Hedwig Schako as the goose girl, on 23 January 1897 and enjoyed some success. However, Else Bernstein-Porges finally relented in 1907 and agreed that Humperdinck could transform the work into an opera.