What opera was the song lilium from?

the song lilium is also from the anime elfen lied in the intro

can download or watch it yourself from youtube and veoh
Update: http://www.youtube.com/watch?v=ZSVlfat4Jqg&feature=related
Update 2: http://www.youtube.com/watch?v=B0hTvjrGSUI&feature=related
1 answer 1