The song is heard most prominently at the start of The Silent Cartographer, during the beach landing and during the end credits.
In its original incarnation, featured frequently in Halo: Combat Evolved, it placed heavy emphasis on deep, powerful percussion instruments and fast paced strings. The starting choir's tempo is 95 bpm (beats per minute), while the middle section speeds up to 120, before the ending choir chant which settles back to 95. The first part of the song is a Gregorian Chant which is repeated at the end, and this is set to a beat of 4 4, with the middle section featuring string instruments and percussion this is set to a beat of 12 8 and is significantly faster than the choir chant. The Halo main theme is set in the key of D major, with two sharps: F and C. The chant from beginning of the Halo Theme.
