
In the seventy-fifth of Ezra Pound's Cantos, Pound asks of Gerhart Münch "Gerhart art thou come forth out of Phlegethon? with Buxtehude and Klages in your satchel, with the Ständebuch of Sachs in yr / luggage".

The river Lethe is also counted among the rivers of the underworld. Milton also mentions the Rivers Styx, Acheron, and Cocytus. In Paradise Lost (II, 580) John Milton names the Phlegeton ( sic) as one of the rivers of Hell, which bold adventuring demons explore while Satan's flight to Earth begins. In Spenser's The Faerie Queene, Phlegethon is found in Hell, and is portrayed as a "fiery flood" where "the damned ghosts in torments fry" (Canto V, 291–291). Dante and Virgil cross Phlegethon with help from Nessus. Centaurs patrol the circle, firing arrows at those who try to rise above their allotted level in the river. The depth at which each sinner must stand in the river is determined by the level of violence they caused in life Dante sees Attila the Hun and Alexander the Great up to their eyebrows. By causing hot blood to flow through their violent deeds in life, they are now sunk in the flowing, boiling blood of the Phlegethon. It is in the Seventh Circle of Hell, which punishes those who committed crimes of violence against their fellow men (see Canto XII, 46–48) murderers, tyrants, and the like. In Dante's Inferno Phlegethon is described as a river of blood that boils souls. The line also reveals the common preoccupation with death and magic found in Roman tragedy.


In Oedipus by Seneca the Younger, the first singing of the chorus, which mainly describes the plague that has settled in Thebes, includes the line, "Phlegethon has changed his course and mingled Styx with Theban streams." While this is not essential to the plot of the play, the line figuratively serves to suggest Death has become physically present in Thebes. Eventually, when Hades allowed her river to flow through, they reunited. It is said that the goddess Styx was in love with Phlegethon, but she was consumed by his flames and sent to Hades. Plato describes it as "a stream of fire, which coils round the earth and flows into the depths of Tartarus". In Greek mythology, the river Phlegethon ( Φλεγέθων, English translation: "flaming") or Pyriphlegethon (Πυριφλεγέθων, English translation: "fire-flaming") was one of the five rivers in the infernal regions of the underworld, along with the rivers Styx, Lethe, Cocytus, and Acheron.
