From "The Land of Smiles"

"The original was a duet for a tenor and contralto and represented the "tear-jerker" moment in the story of an inter-racial romance doomed to failure. It has resonances with the earlier opera by Giacomo Puccini, "Madam Butterfly". The number hit the charts when the famous tenor, Richard Tauber, also an Austrian, like Franz Lehar, recorded it in English. The score supplied was matched with the original German libretto for an amateur performance, which revealed how much Tauber's performance owed to Lehar's musicianship in this beautiful love-song."