Oedipus is Polyneices and Eteocles' father. Before his birth, there was a prophecy that Oedipus would kill his father, thus, his parents abandoned him on a mountain, leaving him to die. Oedipus, however, was taken in by a family in a neighboring land.
Much later, Oedipus unknowingly kills his father and marries his mother, fulfilling the prophecy. When Oedipus dicovers his real identity, he gouged out his own eyes. After his sons imprison him, Oedipus curses them to kill each other their actions.
When the curse is fulfilled by his sons' deaths, Oedipus is horrified and grief-stricken. Creon, the new ruler of Thebes, then sends Oedipus into exile, afraid the gods will punish Thebes for housing Oedipus.
Euripides V