The fourth chasm contains those who practiced magic to see into the future. The heads of these souls have been twisted around and they walk backwards weeping upon their buttocks. Dante pities them, but Virgil objects saying pity for those whom God judges is impious. Virgil proceeds to name various souls imprisoned in this chasm: Amphiaräus, a diviner; Tiresias, the Theban prophet who transformed himself into a woman; Aruns a Tuscan diviner, and Manto, a sorceress and the namesake of Virgil's city, Mantova.
Virgil pauses to describe the early history of his city. From a lake in the Alps, Benacus, which is now called Lago di Garda, flowed the river Mincio. This river formed a marsh in the plains; and Manto lived and died on a piece of land surrounded on all sides by this marsh. After her death, a city was built there and named after her, Mantua. Virgil exhorts Dante to correct people if they say otherwise, and then continues pointing out the prominent of the suffering souls: Eurypylus, who advised the Greek warrior Agamemnon to sacrifice his daughter before going to fight the Trojan War; Michael Scott, a magician; Guido Bonatti, an astrologer; and Asdente, a shoe-maker turned soothsayer. They then move to the next chasm as the Moon sets.
