Many thanks to Brendan Carroll for these clips from Erich Korngold's last opera Kathrin. They come from an extremely rare recording issued only in Austria, featuring a Viennese tenor Walter Anton Dotzer. This Serenade comes from near the beginning, when Francois, the hero, serenades Kathrin outside her bedroom window. .Gorgeous set piece but the story isn't quite as simple as it sounds. The opera is set in 1930 for one thing, in the "present", and the subject is not quite as sugary as one might assume. Interestingly, the librettist is Ernst Decsey, Hugo Wolf's devoted follower and first biographer.
Kathrin is a servant and Francois is a soldier. He seduces her by moonlight and ships out, as soldiers do. She gets pregnant and loses her job - grim reality. As happens to destitute girls, she ends up in dangerous situations, which involve lust, deception and murder. Francois turns up unexpectedly - he's now a freelance musician. He thinks she's killed the villain and goes to jail on her behalf. Years later he's free and goes wandering in the mountains and sings the Wanderer Lied below. He gets a job serenading a woman who turns out to be Kathrin ! All's well after all. Please see my numerous other posts on Korngold and related composers.