A helpful discussion of the plot structure of Oedipus Rex, which includes a useful chart, can be found here: http://www2.cnr.edu/home/bmcmanus/oedipusplot.html (see also the link below). To summarize this discussion even more briefly: The peripeteia occurs when the messenger, desiring to assist Oedipus, reveals that the king and queen are actually his real parents – news that devastates Oedipus. Anagnorisis occurs at this point, since Oedipus now realizes his true identity. This realization leads to his catastrophe.
What does this mean, exactly? The three italicized terms all come from Aristotle’s Poetics and might be defined as follows:
- Peripeteia is a sudden reversal or change, particularly of circumstances or situation. Ideally, everything in a good tragedy leads up to such a reversal, and everything that happens afterwards follows from that reversal. Often irony is involved in such a reversal, as it is in Oedipus Rex.
- Anagnorisis is a sudden recognition or realization, as in Oedipus’s abrupt discovery of the identity of his true parents and thus of his own identity as well. Oedipus thus also realizes that he has indeed killed his father and married his mother.
- Catastrophe is the tragic outcome (or at least the beginning of that outcome) of peripeteia and anagnorisis: the horrors that dominate the conclusion of Oedipus Rex are the direct results of the reversal and recognition Oedipus has just experienced.
Aristotle, who prized complex unity in a tragedy, was especially impressed that Sophocles had managed to make the reversal, recognition, and catastrophe in Oedipus Rex occur almost simultaneously. Doing so took great skill and design and produces a powerful impact when the play is read or performed.
In one translation of the play (see link below), the moment of reversal and recognition is rendered in these words, spoken by Oedipus:
Ah me! ah me! all brought to pass, all true!
O light, may I behold thee nevermore!
I stand a wretch, in birth, in wedlock cursed,
A parricide, incestuously, triply cursed!
Shortly following this moment, Oedipus, after discovering that his mother has committed suicide, blinds himself– a catastrophe if there ever was one. No wonder that Aristotle considered Oedipus Rex almost a perfect example and model of an ideal tragedy.