Why Is Antigone's Family Backstory Important?

Antigone comes from royalty. Creon, the new ruler of Thebes, has declared that Eteocles will be honored and Polyneices disgraced. The rebel brother's body will not be sanctified by holy rites, and will lay unburied to become the food of carrion animals. Antigone and Ismene are the sisters of the dead brothers, and they are now the last children of the ill-fated Oedipus. Antigone refuses to adhere to Creon's royal decree.