This post refers to the Greco-roman mithology, fables and legends set to be lost in the time and I’ve always learned why some rites, ceremonies or actions are well in the present.
As indicated in the title, Cerberus (Greek: “guardian of the well”) was the dog of underworld where Hades ruled with his wife Persephone as subjects taking the dead.
After crossing the river in Charon‘s boat, and have paid for the trip with the respective coins that left them in the eye after his funeral, were Cerberus. They could not go back to living together once they had taken a meal in Hell, so the function was feared Cerberus guarding the gates of Hades, to ensure entry and stop living off the dead.
The picture of him was given most often was a three-headed monster dog, a queue formed by a serpent, and in the back, many snakeheads. The name of the heads was: veltesta, tretesta and drittesta (head left, right and third seed head).
Was chained to the door of Hell and souls terrified as they entered, but on several occasions it was possible through the doors teasing the animal. For example, when Orpheus seeking his beloved Eurydice that fell dead from the bite of a serpent, entered the underworld by playing his lyre and getting Cerberus to sleep peacefully.
One of the twelve labors of Hercules command Eurystheus was to look into Hell and bring him back to Earth. Hades allowed him to take it with the condition of Cerberus dominate without being hurt and not use weapons. Hercules fought him hand to hand, and almost got beat drowning. He presented it back to Eurystheus, who shies away, told him that it returned to its origin.
Cerberus, beyond being a mythological creature has deeper functionality, is a Psychopomp being, ie a being who leads souls to their fate: Death. Normally these animals were wild dog, wolf or jackal; hence Romans and Greeks consider dogs as messengers of the gods.
Not only were they who saw them as a guardian animal, but that’s another story …
– Grimal, P. Diccionario de Mitología Griega y Romana, Ed. Paidós .