When Oedipus stepped down as King of Thebes, he gave the kingdom to his two sons, Eteocles and Polynices, who both agreed to alternate the throne every year. However, they showed no concern for their father, who cursed them for their negligence. After the first year, Eteocles refused to step down and Polynices attacked Thebes with his supporters (the Seven Against Thebes). Both brothers died in the battle.
See also Epigonoi