I must tell you that King Atlas, having in the olden time helped the Titans in their wars against the gods, was undergoing punishment for this offence, his penance being to hold up the starry vault of heaven upon his shoulders. This means, perhaps, that in the kingdom of Atlas there were some mountains so high that their summits seemed to touch the sky.
Hercules offered to relieve Atlas of his load for a time, if he would but tell him where the famous tree was, upon which grew the golden fruit. Atlas consented, and for some days Hercules supported the earth and the starry vault of heaven upon his shoulders.
Then Atlas opened the gate of the Garden of the Hesperides to Hercules. These Hesperides were none other than the three daughters of Atlas, and it was their duty, in which they were helped by a dragon, to guard the golden apples.
Hercules killed the dragon and carried off the apples, but they were afterwards restored to their place by Minerva.
Cerberus, as perhaps you know, was the triple-headed dog that guarded the entrance to the nether world. To bring up this three-headed monster from the land of the dead was the last of the twelve labors. It was also the hardest.
Pluto, the god of the nether world, told Hercules he might carry off the dog if he could take him without using club or spear—never dreaming that the hero could perform such a difficult feat.
Hercules penetrated to the entrance of Pluto's gloomy regions, and, putting forth his strength succeeded, not only in seizing Cerberus, but also in carrying him to Eurystheus, and so brought the twelve labors to an end, and was released from his servitude to his cruel brother.
These exploits of strength and endurance do not by any means complete the tale of the wonderful doings of the great Greek hero. He continued his deeds of daring to the end of his life.
One of the last of his exploits was to kill the eagle that daily devoured the liver of Prometheus, whose story is both curious and interesting.