Towards the end of Sophocles's Oedipus Rex, a messenger from Corinth arrives at Oedipus's palace to give Oedipus news that King Polybus of Corinth, whom Oedipus believes is his real father, has died.
The messenger also reveals that King Polybus and his queen, Merope, are Oedipus's adoptive parents, not his real parents, and Oedipus orders that a shepherd who has knowledge of this be brought before him.
Oedipus's queen, Jocasta, tries to dissuade Oedipus from talking with the shepherd. When Oedipus insists on seeing the shepherd, Jocasta goes into the palace, with an ominous remark to Oedipus that foreshadows events that will play out very soon.
JOCASTA. [to Oedipus] O woe is thee, poor wretch! With that last word
I leave thee, henceforth silent evermore.
Oedipus learns from the shepherd that Polybus and Merope were, indeed, his adoptive parents. He also learns that his real parents are Laius, the former king of Thebes whom Oedipus killed on the road to Thebes, and Laius's queen, Jocasta, his own queen, and, as he's discovered, also his own mother.
Oedipus rushes away into the palace.
After a short choral interlude, a messenger comes from the palace to say that Jocasta has hanged herself. The messenger also tells how Oedipus forced his way into the room where Jocasta died.
MESSENGER. He crashed against
The folding doors, and from their staples forced
The wrenched bolts and hurled himself within.
...But when he saw her, with a maddened roar
He loosed the cord; and when her wretched corpse
Lay stretched on earth, what followed—O 'twas dread!
He tore the golden brooches that upheld
Her queenly robes, upraised them high and smote
Full on his eye-balls...
The brooches that fastened Jocasta's "queenly robes" can be said to symbolize her position as queen, both to her current husband, Oedipus, and to her former husband and Oedipus's father, Laius.
The messenger says that Oedipus cried out, "No more shall ye behold such sights of woe, / Deeds I have suffered and myself have wrought!" and that Oedipus continued to stab at his eyes with Jocasta's brooches.
MESSENGER. Not once but oft, he struck with his hand uplift
Oedipus comes from the palace, his eyes bleeding from the self-inflicted wounds. The leader of the chorus asks Oedipus why he did this, and Oedipus replies that Apollo—meaning fate and the will of the gods—is responsible for everything that has happened to him but that he is the instrument of his own tragic downfall.
LEADER. O doer of dread deeds, how couldst thou mar
Thy vision thus? What demon goaded thee?
OEDIPUS. Apollo, friend, Apollo, he it was
That brought these ills to pass;
But the right hand that dealt the blow
Was mine, none other.