Dude, you rock!Hey guys, long time no post.
From the sound byte (and a helpful dollup of Shazam) the track at 20:21 is "Finale", by Elliot Goldenthal, on the Titus soundtrack. I can't confirm it, as I'm having trouble finding a full sample of the track (there is a sample here: http://us.dada.net/music/elliotgoldenthal/victorius-titus_244675m.html, but not the same part of the song) but I'm 80% sure.
EDIT: Found the album, and it is Finale. Great track!