"The Prophet's Song" was composed by Brian May. On the showIn 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. Portions of the song were recorded but abandoned during sessions for Queen II. May 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, it 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 also admitted the guitar's lowest E2 string is tuned down to a D2 note, a rarity at the time. May plays a non-standard Queen instrument, a toy koto, during the introduction and closing "wind" sections of the song. Producer Roy Thomas Baker recalled in a documentary of the making of the song that the wind effect was created by recording the sound of an air-conditioning unit through a phaser. 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 lyric refers to the Book of Genesis, explicitly in examples such as "return like the white dove", and cryptically in examples such as a vision of a "moonlit stair" comparable to Jacob's Ladder.
Reception
has called the song "mystical prog rock", citing it as an epic as fascinating as "Bohemian Rhapsody" and one of Queen's finest studio achievements. Rolling Stone also praised it, naming it as the record's "best track", noting that "May's powerful guitar perfectly complements the rich, multitracked harmonies of lead singer Freddie Mercury." Ultimate Classic Rock has also called the song "epic and mystical art rock".
