The Beginning of Oedipus Rex

It takes three times of readings for me to really understand the drama, Oedipus Rex. From the prologue, I would say that Oedipus is a responsible king who tries to save his people from the plague. His intention is good. However, his overconfidence seems to drive him to unveil the darkest secret that he would never want to face. Personally, I felt that Oedipus should not be led to such tragic ending. Just look at the way he is so brave to kill Sphinx for Thebes and his determination to bring his people out of the plague. Although he is a little bit overconfident and lacks of discretion, nobody would ever predict the ending to be in such a way.