“Knights of Cydonia” is the final track on the non-Japanese pressings of Black Holes and Revelations, and was once described by bassist Chris Wolstenholme as “40 years of rock history in six minutes.”

This song combines the subjects of Mars and the Four Horsemen of the Apocalypse mentioned in the Book of Revelations in The Bible. The Four Horsemen of the Apocalypse appear in chapter 6 v 2-8. The four horses represent God’s judgment of people’s sin and rebellion and are a foretaste of the final judgment to come. The four horsemen are traditionally named pestilence, war, famine, and death.

This song, like much of Black Holes and Revelations, is inspired by corrupt political leaders. Matthew Bellamy says its not about any specific leader, but all leaders. Evidence of this is shown in the lyrics, such as “I’ll show you a ‘god’ who falls asleep on the job,” referring to leaders who treat themselves like God because they have power.

Cydonia is the region on Mars where some believe life has existed. In the January 2007 issue of Q magazine, Matt Bellamy said: “I’d definitely be up for a trip to Mars. I’d love to record an album at zero gravity. Or at least go up there and do a vocal take. The area of Cydonia is very interesting. There are parts of it that resemble abandoned civilizations.”

Since 2008, live performances have included an introduction of Ennio Morricone’s “Man With a Harmonica” from Once Upon a Time in the West where bassist Chris Wolstenholme plays a harmonica piece.

The song was included in Guitar Hero III: Legends of Rock.