[395] _Duke of Athens_: Theseus, instructed by Ariadne, daughter of Pasiphaë and Minos, how to outwit the Minotaur, entered the labyrinth in the character of a victim, slew the monster, and then made his way out, guided by a thread he had unwound as he went in. [396] _The slippery waste_: The word used here, _scarco_, means in modern Tuscan a place where earth or stones have been carelessly shot into a heap. [397] _The new weight_: The slope had never before been trodden by mortal foot. [398] _The former time_: When Virgil descended to evoke a shade from the Ninth Circle (_Inf._ ix. 22). [399] _Prey from Dis_: The shades delivered from Limbo by Christ (_Inf._ iv. 53). The expression in the text is probably suggested by the words of the hymn _Vexilla: Prædamque tulit Tartaris_. [400] _To Chaos_: The reference is to the theory of Empedocles, known to Dante through the refutation of it by Aristotle. The theory was one of periods of unity and division in nature, according as love or hatred prevailed. [401] _Another spot_: See _Inf._ xxi. 112. The earthquake at the Crucifixion shook even Inferno to its base. [402] _The river of blood_: Phlegethon, the 'boiling river.' Styx and Acheron have been already passed. Lethe, the fourth infernal river, is placed by Dante in Purgatory. The first round or circlet of the Seventh Circle is filled by Phlegethon. [403] _Centaurs_: As this round is the abode of such as are guilty of violence against their neighbours, it is guarded by these brutal monsters, half-man and half-horse. [404] _Chiron_: Called the most just of the Centaurs. [405] _Nessus_: Slain by Hercules with a poisoned arrow. When dying he gave Dejanira his blood-stained shirt, telling her it would insure the faithfulness to her of any whom she loved. Hercules wore it and died of the venom; and thus Nessus avenged himself. [406] The natures: The part of the Centaur where the equine body is joined on to the human neck and head. [407] _Other band_: Of Centaurs. [408] _Alexander_: It is not known whether Alexander the Great or a petty Thessalian tyrant is here meant. _Dionysius_: The cruel tyrant of Syracuse.