https://en.wikipedia.org/wiki/The_Battle_of_Evermore
Sandy Denny
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. 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 played the role of the narrator and Denny represented the town crier. Page elaborated that "[The song] sounded like an old English instrumental first off. Then it became a vocal and Robert did his bit. Finally we figured we'd bring Sandy by and do a question-and-answer-type thing."[8]
https://en.wikipedia.org/wiki/Sandy_Denny
