Greek underworld his duty was to bring these souls to the underworld and no one would persuade him to do otherwise. Cerberus (Kerberos), or the "Hell-Hound", is Hades' massive multi-headed (usually three-headed) dog with some descriptions stating that it also has a snake-headed tail and snake heads on its back and as its mane. Born from Echidna and Typhon, Cerberus guards the gate that serves as the entrance of the underworld. Cerberus' duty is to prevent dead people from leaving the underworld. Heracles once borrowed Cerberus as the final part of the Labours of Heracles. Orpheus once soothed it to sleep with
The Dog It Was That Died be seen as the mad dog of the poem. Stoppard may have borrowed the idea to use this quotation from British novelist W. Somerset Maugham's 1925 "The Painted Veil", in which the protagonist's husband, bitter at her infidelity, brought her to cholera-stricken China in hopes that she would take ill and die. When he catches cholera instead, he dies with the quotation "The dog it was that died" on his lips. The words also occur in a speech by Wormold, the lead character in Graham Greene's 1958 novel "Our Man in Havana" – also an entertaining tale of Cold War