In Greek mythology, Cerberus or Kerberos (Greek Κέρβερος Kerberos, demon of the pit), was the hound of Hades—a monstrous three-headed dog (sometimes said to have 50 or 100 heads) with a snake for a tail and innumerable snake heads on his back.
He was overcome several times:
- Heracles' final labour was to capture Cerberus, which he did by treating it with the first kindness it had ever received.
- Orpheus used his musical skills to lull Cerberus to sleep.
- Hermes puts him to sleep with water from the river Lethe.
Heracles' capturing of Cerberus
Heracles' final labour was to capture Cerberus. After having been set the task, Heracles went to Eleusis to be initiated into the Eleusinian Mysteries so that he could learn how to enter and exit the underworld alive, and in passing absolve himself for killing centaurs. He found the entrance to the underworld at Taenarum and Athena and Hermes helped him to traverse the entrance in each direction. He passed Charon thanks to Hermes' insistence, and his own heavy and fierce frowning.
Whilst in the underworld, Heracles freed Theseus but the earth shook when he attempted to liberate Pirithous, so he had to leave him behind. They had been imprisoned by Hades, by magically binding them to a bench, because they had attempted to kidnap Persephone. The magic was so strong that when Heracles pulled Theseus free, part of Theseus' thighs remained on the bench, explaining why his descendants had notably lean thighs.
In some versions, Heracles merely asks Hades for permission to take Cerberus, to which Hades agrees as long as Heracles does not harm the hound, though in other versions Heracles shot Hades with an arrow. In some versions, Heracles wrestles the dog into submission and drags it out of Hades, passing through the cavern Acherusia, but in other versions, Heracles treats the vicious dog with the first kindness it has seen, and easily walks out with it.