The Inferno is a 14th-century epic poem by Dante Alighieri recounting the narrator's tour of hell. Midway through life, the narrator is lost in a dark woods. The Roman poet Virgil saves him, leading him into the underworld, past the river Acheron, into hell itself. Virgil explains the sinners and punishments, each of which are proportional and similar to the sins committed. The pair travel through the nine rings of hell, through limbo, lust, gluttony, greed, wrath, heresy, violence, fraud and finally treachery, where Satan tortures Brutus, Cassius and Judas.