The task of capturing Cerberus alive, without using weapons, was the final labour assigned to Hercules by King Eurystheus, in recompense for the killing of his own wife and children after he was driven insane by Hera, and therefore was the most dangerous and difficult .
After having been given the task, Hercules went to Eleusis to be initiated in 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 Tanaerum, and Athena and Hermes helped him to traverse the entrance in each direction. He passed Charon with Hestia's assistance and his own heavy and fierce frowning
In the underworld, Hercules met Hades and asked his permission to bring Cerberus to the surface, which Hades agreed to if Hercules could overpower the beast without using weapons. Hercules was able to overpower Cerberus and proceeded to sling the beast over his back, dragging it out of Hades through a cavern entrance in the Peloponnese and bringing it to Eurystheus. The king was so frightened of the beast that he jumped into a pithos, and asked Hercules to return it to the underworld in return for releasing him from his labours.