Page elaborated that " sounded like an old English instrumental first off. Plant played the role of the narrator and Denny represented the town crier. Denny was a former member of British folk rock group Fairport Convention, with whom Led Zeppelin had shared a bill in 1970 at the Bath Festival of Blues and Progressive Music. Plant felt he needed another voice to tell the story, and for the recording of the song, singer Sandy Denny was invited to duet with Plant. Describing the effect of the song, it writes that Plant makes use of the feeling of nostalgia with the "strain and desperation" in his "vocal cries" combined with the "haunting, pastoral soundscape" that together set up "the destructive world of war in opposition to an idealized and Arcadian peaceful home". It states that the battle in the song "has often been identified by fans" as the Battle of the Pelennor Fields. It notes that the song "specifically alludes" to the Dark Lord and the Ringwraiths, while the "Queen of Light" mentioned is "possibly" the elf-queen Galadriel. The Oxford Handbook of Music and Medievalism treats the song as "fantasy medievalism", seeing allusions to multiple features of Tolkien's Middle-earth. Tolkien Encyclopedia states that the three songs make "direct references to Gollum, Mordor, the Ringwraiths, and events described in The Silmarillion and ". Tolkien, with "The Dark Lord rides in force tonight and time will tell us all" in line 4, "The drums will shake the castle wall, the Ringwraiths ride in black" in line 18, and mentions of war and swords (line 13), shooting with a bow (line 19), magic runes (line 20) and "the dragon of darkness" in line 24.
The song, like Led Zeppelin's " Ramble On" and " Misty Mountain Hop", makes references to The Lord of the Rings by J. Further information: Works inspired by J.