The labors of Hercules
The Ancient Greek (and later Roman) myth of Hercules tells the story of a man who performed 12 difficult tasks ("labors") to redeem himself after being made to kill his family. He was the son of Zeus, the king of the gods, and Alcmane, a mortal woman. Hera, Zeus' wife, obviously took issue with this, and tried to kill Hercules at multiple points in his childhood, the most famous of which being when she sent two venomous snakes to kill him in his crib. Hercules strangled them. Later, when he is a married adult with two children, she causes him to fall into madness, killing his children, and, in some versions of the myth, his wife. Grief-stricken, he visits the Oracle of Delpi to ask what he should do to atone. She tells him to complete 10 (later expanded to 12) labors for his cousin, Eurystheus.