Sophocles

In 468 BC, Aeschylus was defeated in the tragedy competition by Sophocles. Sophocles' contribution to drama was the addition of a third actor and an emphasis on drama between humans rather than between humans and gods. Sophocles was a fine craftsman. 

Aristotle used Sophocles' play, Oedipus Rex for his classic analysis of drama, The Poetics. Sophocles' plays are suffused with irony. In The Oedipus Trilogy, Oedipus seeks the truth about his father's murder. The truth that awaits him, however, is that he is the murderer.    

In Electra, the hunted murderer Aegisthus finds the identity of a body under a blanket is Orestes, the man who has relentlessly hunted him and his lover, Clytemnestra. He is relieved that he has escaped justice. However, when he lifts the blanket he discovers the body is that of his lover Clytemnestra. Orestes has indeed caught up with him. 

Sophocles' plays are about the folly of arrogance and the wisdom of accepting fate. Sophocles believed in the Greek gods, but his plays are suffused with existential insights that have been voiced many times since. For instance, compare this observation by Antigone: What joy is there in day repeating day, some short, some long, with death the only end? I think them fools who warm their hearts with the glow of empty hopes.