"Die Lorelei" is arguably the most famous of German folk songs, certainly it is the best known in the English speaking world. The Lorelei (or Loreley) is a rock on the River Rhine, and herein it becomes a mermaid or siren, doing what these fascinating but deadly creatures do best, luring hapless sailors to their deaths.
The song about this particular Rheine Maiden was actually written as a poem by Heinrich Heine (1797-1856) and published in 1827; it was set to music by Friedrich Silcher (1789-1860). Heine was a Jew, and during the Nazi era an attempt was actually made to suppress the song, but the German people wouldn't stand for this, so the name of the author was quietly forgotten in that time, although Heine is today one of the most famous German poets.
"Die Lorelei" has been recorded by numerous artists over the years, and remains popular as both a folk and a classical work.