Why did Aristotle believed that Oedipus the King was the perfect tragedy?

In his Poetics, Aristotle outlined the ingredients necessary for a good tragedy, and based his formula on what he considered to be the perfect tragedy, Sophocles'sOedipus the King ... A good tragedy will evoke pity and fear in its viewers, causing the viewers to experience a feeling of catharsis.

In Aristotle's Poetics, he outlines the major principles of tragedy, citing Sophocles' Oedipus as the paragon of the form. Aristotle's reasons are clear: to be the perfect tragedy the play must have a perfect plot. Oedipus follows the classic Aristotelian triangle of rising action, climax, and falling action. The play is full of dramatic irony (the audience knows more than the tragic hero) and verbal irony (the use of sarcasm, understatement, and overstatement).