Oedipus Rex by Sophocles can certainly serve as an archetype of Aristotelian tragedy. As defined by Aristotle in his Poetics, tragedy is
...an imitation in dramatic form of an action that is serious and complete, with the incidents arousing pity and fear wherewith it effects a catharsis of such emotions....The chief characters are noble personages ....The plot involves a change in the protagonist's fortune.
1. The plot is serious and complete - In Oedipus Rex, the city of Thebes suffers from a plague and is ravaged by fire; therefore, the citizens seek the aid of King Oedipus, who has previously saved the citizens from death by solving the riddle of the Sphinx, who subsequently destroys itself. When he returns from Delphi, Creon tells the king,
I shall say all I heard from the god.(105)
Phoebus clearly ordered us, my lord,
to drive out the pollution being fostered
in this very land, not to nurture it unhealed
In his efforts to save Thebes, Oedipus, then, interviews the blind seer Teiresias in order to learn the cause of the plague. In so doing and by calling upon others such as the shepherd, Oedipus eventually learns the terrible truth that he himself is the cause of the city's misery. With this knowledge, Oedipus blinds himself and leaves Thebes.
2. The tragic fall of the protagonist, a noble character, is his/her own fault brought upon by his/her hamartia, a criminal act committed in ignorance of some fact, or for the greater good. In Oedipus Rex, for example, Oedipus, who has been told that he will kill his father has moved away and gone to another place to live, however, he ironically comes to his birthplace, unknowingly marries his mother Jocasta, and effects the tragic consequences for Thebes, "the pollution."
However, because he is of noble character, Oedipus seeks to aid Thebes as its king. In this effort, Oedipus experiences a discovery and a reversal of fortune, two other components of the Aristotelian tragic hero. As Oedipus, in his pride, argues with Teiresias, he is told that he will soon be cursed himself, as he "weaves" his own doom:
Do you know your true descent? And secretly
you are an enemy to your own kin,
both under the earth and on it. Striking you
from both sides the terrible hounds of your mother’s
and father’s curse will drive you from this land;(440)
though you see well enough now, then you will be blind
The seer's words do come true and Oedipus blinds himself in his angst at this discovery that he is the murderer of the former king, Laios, that the city seeks. Oedipus falls from great heights to a tragic end as he learns that he has killed his father, married his mother, and in this incestuous relationship, he has fathered children.
3. There is a catharsis. Certainly, the audience of Oedipus Rex feels pity and fear for Oedipus when he attains the knowledge that he is the perpetrator of the misery of Thebes, and when he blinds himself. Nevertheless, there is also Oedipus's new knowledge of himself and wisdom which affords the audience the uplifting recognition of human greatness.