Why did iron maiden use the rime of ancient mariner in their song?

The Rime of the Ancient Mariner is a poem written by Samuel Taylor Coleridge in 1797-98. Bruce Dickinson the lead singer of Iron Maiden liked reading the poem in school and felt that it had heavy metal themes. He felt that The Rime of the Ancient Mariner also provided a structure that they could build a complex instrumental around so they used the poem as the inspiration for their song of the same name.