In "Antigone", what did Polynieces do to betray someone?Wasn't he king of the kingdom but went agaisnt his own people and that lead to his death...

Polyneices was the brother of Eteocles. Their father was Oedipus. When Oedipus left Thebes in exile after finding out he had killed his father and married his own mother, he put both brothers on the throne. The brothers were supposed alternate years when each was king. In other words, one year Eteocles was supposed to be king and the next year he was to give the leadership of Thebes to his brother, Polyneices. However, Eteocles refused to give up his throne when the time came for Polyneices to be king. So, Polyneices raised an army and attacked Thebes. In the battle, both brothers were killed. Their uncle, Creon, took the throne and decried that since Polyneices had fought against his own people, he was not to be buried. This fate would condemn his soul to wander the earth for 100 years. That is why his sister, Antigone, is so anxious to bury Polyneices and why she disobeys Creon's edict.