Dante Alighieri, an Italian writer of the fourth century, wrote an epic famous for its theme and formal mastery: The Divine Comedy. It is a work written in verse that throughout three books - hell, paradise and purgatory - explains the dilemma of Christian death and the sins committed by humans.
The first verse of the song alludes to the trip that the protegonist will undertake along with Virgilio, the classic Latin writer, by the nine circles of the hell. This journey is included in the first book of the Divine Comedy, called "L´Inferno".