On one of his adventures, Herakles helped to save the city of Thebes. The King of Thebes was so thankful that he offered Herakles his daughter's hand in marriage. Megara and Herakles were very happy together and had many children. Although Herakles was now a grown man with a family of his own, Hera was still filled with a desire to destroy him. One night she sent him a terrible dream that drove him mad. During his madness Herakles murdered his wife and all their children. When he woke up and realised what he had done Herakles was devastated. He was filled with grief and horror, and went to the temple at Delphi to beg forgiveness for what he had done. The priestess at the temple told him to go to King Eurystheus of Tiryns, and offer himself as a servant. She said that when he had served the king for twelve years and done all that was asked of him, he would be forgiven.