I first heard this song upon listening to Haggard's Eppur Si Muove, a band and an album recommended to me by someone on Metal From Finland. I loved this immediately: so atmospheric, so achey, so beautiful...And I didn't understand a single word!
According to Wikipedia, Herr Mannelig is a Swedish ballad about a female mountain troll who wants to marry a knight. The lyrics can be found here, in both Swedish and English. Wikipedia says that Haggard performs the song in Italian, even though they are a German band.
Here is "Herr Mannelig" being performed in Swedish by the band In Extremo, a German medieval metal group.
Here is a Belarusian version done by Litvintroll, a folk metal band from that country.
And here is my favourite version, sung by Haggard! And yes, I chose the LoTR video on purpose!
Which one do you prefer? I think all of them are interesting in their own way, and as a good cover should do, each band brings their own character into the song. But I have a special place in my heart for the Haggard version because I think it really captures the emotion of the lyrics. I also love the sound of the guitar in this song; it's so crisp.