Music of Halo 2

The music of Halo 2 is the musical score to Halo 2.

Development
One of the first tracks composed for Halo 2 was The Last Spartan, which was the backing track for the 2002 Halo 2 announcement trailer. The Last Spartan is representative of many compositions in Halo 2, where composers Martin O'Donnell and Michael Salvatori introduced new motifs, while reusing and incorporating musical themes from Halo: Combat Evolved. In the case of The Last Spartan, the track begins with its own motif before ending with Cloistered Expectancy, the Halo 2 rendition of the Gregorian chant. Other examples include Impend, which opens with the ending of Brothers in Arms, and Heretic, Hero, which opens with its own melody before incorporating the main melody of A Walk in the Woods in its second half. Wage featured both the melodies of Under Cover of Night and The Maw at a different tempo. Other than the Gregorian chant, only two tracks in Halo 2 were outright arrangements of tracks from Halo: Combat Evolved: Remembrance (arrangement of The Maw) and Cold Blue Light (arrangement of the fourth section of Opening Suite). The Last Spartan also demonstrated the reuse of motifs introduced in Halo 2, with its motif incorporated into two other tracks that were composed in the early stages of the development. Skyline and Earth City, likely written early in production for inclusion in the 2004 Halo 2 E3 demo, incorporated the main motif of The Last Spartan as well as the Gregorian chant from the Halo Theme.

In addition to The Last Spartan, Halo 2 also introduced new motifs. Most notably, Weight of Failure, along with its alternate versions, featured a solemn melody that served as the leitmotif for Arbiter Thel 'Vadam, with the name alluding to his defeat at Battle of Installation 04. The same melody was incorporated into Ghosts of Reach, and would appear in its Halo 3 rendition Black Tide in Dread Intrusion. Another motif, Penance, featured what Martin O'Donnell coined "Halo 2 monk theme", which served as leitmotif for Installation 05. The motif first accompanied the reveal of Installation 05 in the level Delta Halo, and then reprised when the ring's activation was interrupted in the final level The Great Journey. The same melody was incorporated into Leonidas, and would appear in its Halo 3 rendition Leonidas Returns in Three Gates.

Halo Trilogy: The Complete Original Soundtracks
In 2008, after the release of Halo 3, a box set was released, featuring the Halo: Original Soundtrack, the Halo 2: Original Soundtrack, Volume 2, and the Halo 3: Original Soundtrack.