Originally Posted by SR22

I think you are thinking of Man On Fire. The scene at the end when Creasy (Denzel Washington) trades his life for Pita.

EDIT: Did a little research, and it turns out the song is written by someone named Lisa Gerrard. It turns out, she wrote and performed music for Gladiator and Man on Fire. The song is called "Now We Are Free" in Gladiator. Apparently (depends on the source) the last two minutes of the song were used in the scene I described. They called it "Creasy Dies" in Man On Fire. So, perhaps you were thinking of Gladiator.