The words are definitely not traditional (I wrote to "Rise Up Singing" and they will correct it in a later edition), but by Heinrich Heine (the story is traditional). You might be interested to read how the author was "lost".
When the Nazi were in power they first tried to eliminate everything Jewish from the German culture (it is well know n how far their idea of elimination went in later years). They eliminated for instance names of German jews from the history books, at least in all positve connections. They didn´t print anymore any stories, books, music by jews. But when they were compiling books with German (folk)songs they had a problem with "Die Lorelei". To print this song with the hated name Heine as author was unconceivable for them, to omit this particular song which rates among the top five on the popularity scale also could not be done. Their solution for this dilemma was to call it "traditional" which they knew it wasn´t. This makes you understand why I insist that this particular song gets its author back.

Wolfgang