Back in 1999, the year Sigur Rós released their international breakthrough, Agaetis Byrjun, Jón Þór “Jónsi” Birgisson wrote the following mission statement on his band’s website: “We are not a band, we are music … We are simply gonna change music forever, and the way people think about music. And don’t think we can’t do it, we will.” As we all know, that kind of overblown arrogance isn’t unusual in the pop music mainstream. (Among other quotable tidbits, Kanye West recently told W Magazine, “I’m the No. 1 living and breathing rock star. I am Axl Rose; I am Jim Morrison; I am Jimi Hendrix.’”) Still, that sort of sentiment felt awfully strange coming from the mild-mannered frontman of an obscure Icelandic post-rock band.