The Halo theme originates from Halo: Combat Evolved, released in 2001 for the Xbox. Composed by Martin O'Donnell and Michael Salvatori, its choral opening became one of the most recognizable pieces of video game music. Short clips of the theme spread widely through machinima, gaming montages, memes and nostalgic edits, especially on YouTube and later short-form video platforms. It remains popular because a second or two is enough to signal Halo instantly and give any scene a huge sci-fi, heroic atmosphere.