"The Prophet's Song" was composed by Brian May (working title "People of the Earth"). On the show In the Studio with Redbeard, which spotlighted A Night at the Opera, he explained that he wrote the song after a dream he had about a great flood while he was recovering from being ill while recording Sheer Heart Attack, and is the source of some of the lyrics. He spent several days putting it together, and it includes a vocal canon sung by Freddie Mercury. The vocal, and later instrumental canon was produced by early tape delay devices. It is a heavy and dark number with a strong progressive rock influence and challenging lead vocals. At over eight minutes in length, is also Queen's longest song with vocals, though the untitled instrumental track from Queen's last studio album, Made in Heaven, is about 14 minutes longer.
May plays a non-standard Queen instrument, a toy koto, during the introduction and closing "wind" sections of the song.
As detailed by May in a documentary about the album, the speed-up effect that happens in the middle of the guitar solo was achieved by starting a reel-to-reel player with the tape on it, as the original tape player was stopped.
The dream May had was about The Great Flood, and lyrics have references from Book of Genesis and the Noah's Ark account. The Flood is nowadays thought by researchers to have originated in the Black Sea, or Pre-Euxine Lake, when the Mediterranean breached the Bosporus Strait and water levels rose within an accelerated time-frame (see The Black Sea Hypothesis). The theory is backed up by biological evidence such as freshwater seashell remains, and by archaeological timelines of the ancient cultures from the Romanian and Bulgarian coasts. However, the Ark itself remains a mythological complex built from references to subsequent migrations and the origins of various tribes, which maintain a link to the original Pre-Euxine Lake civilization.
- Freddie Mercury - lead and backing vocals
- Brian May - guitars, backing vocals, toy koto
- Roger Taylor - drums and backing vocals
- John Deacon - bass guitar