In Sophocles' Oedipus the King, the title character discovers that he has killed his father, Laius, and married his mother, Jocasta. When Oedipus is on the verge of discovering the truth, Jocasta rushes back into the palace because she realizes that Oedipus is about to learn his true identity.
After Oedipus learns the truth, he also rushes back into the palace in search of Jocasta. When he finds her, she has hanged herself. Oedipus then takes her down, removes the brooches that Jocasta was wearing on her dress, plunges them into his eyes. When he does this, he cries out to his eyes:
"You will no longer see
all those atrocious things I suffered,
the dreadful things I did! No. You have seen
those you never should have looked upon,
and those I wished to know you did not see.
So now and for all future time be dark!"
(A.S. Kline translation)