> Yes I know that some of the battle music on the soundtrack interpolates
> variations on "Mars, the Bringer of War" from Gustav Holst's
> "The Planets". But if you think, it is an inside joke, since
> Mars was the war god in the Roman Empire.

You are correct when you say that mars was the Roman god of war. But, that is not what Holst had in mind when he was composing "The Planets". Holst based his movements on each planets astrological significance, not are their position in ancient Roman religion.