I really like the melody of this song, even Elvis liked it too. I often heard it since I was,...mmm...., can't remember. Then I started to pay more attention to the melody after I heard Jeff Beck's version in Marry Axemas.
At first I thought it was a Christmas song, but a friend told me that actually it's a folk song, a hymn and the lyrics was written by John Newton. (Here for more info) The song tells about anti-slavery message: how a captain of slave delivery ship finally realized what he had done was a very evil deed. (There's a movie too about the creation of song, but I forgot the title).
About the song, it started with me just sitting in front my computer. I got the drum roll wav from AoE II and tried to make slight variations, here and there. I thought the atmosphere was a bit glorious, hymnic, and kind of longing, then the idea of using it for this song appeared. Sought for the best instruments, sound, and effects. I've tried to make an ensemble of trumpets and other wind instruments, but couldn't got it well with my FL.
So I ended up with those strange sounds. I put the robotic speech in random, sort of chaotic whispers and one them actually saying "I can't feel no better". I arranged them up and thought that would do for this version.