The Oedipus myth goes back as far as Homer and beyond, with sources varying about plot details. The play that Sophocles presents is merely the end of a dramatically long story, and some plot background must be provided to make the story understandable for modern audiences (please see the section on ‘Oedipus and Myth’ for this full backstory). The real myth begins a few generations before Oedipus was born. The city of Thebes was founded by a man named Cadmus, who slew a dragon and was instructed to sow the dragon's teeth in order to give birth to a city. From these teeth sprang a race of giants who were fully armed and angry; they fought each other until only five were left, and these five became the fathers of Thebes.
Ancient Greek audiences would already know the background, and in fact the entirety, of the Oedipus story. Therefore what makes this particular play so great is its ability to present this material in an evocative and powerful manner, in order to nullify the reality that most of the audience already knew its contents. Modern audiences might recognize the name Oedipus from Sigmund Freud's famous "Oedipus Complex" - particularly his theory that young boys lust after their mothers and see their fathers as competition for their mothers' favors. This theory springs from Jocasta's comment that killing your father and marrying your mother are the kinds of things men often dream of (981). Freud's theory has been hotly debated and, indeed, is currently dismissed by most classical scholars – though the fact that the issue remains the subject of much psychological debate is proof that the Oedipus story continues to be powerful even thousands of years after the advent of Sophocles' play.