The National on a soundtrack to the Game of Thrones

The National revealed a song from upcoming Game of Thrones season 2 soundtrack, called Rains of Castamere. The song's lyrics come from G.R.R. Martin's books, and if you want to read about it's history within A Song of Ice and Fire universe, head over here. BE WARNED, THE SITE CONTAINS SPOILERS. All I can say, it's about lord Tywin Lanister and his victory against rebels prior to the events of the books and series. You can hear the song below.