Aristotle
A tragedy is the imitation of an action of some magnitude that is serious and also complete in itself, in language with pleasurable accessories [rhythm and harmony], in a dramatic, not a narrative form, with incidents arousing pity and fear, to accomplish its catharsis of such emotions.
Elements are these:
Plot--most important, should be complex
Character--tragic hero--elevated; brought down
Diction
Thought
Spectacle
Melody
Peripety--change from one state of things within the play to its opposite
Discovery--a change from ignorance to knowledge, and thus either to love or hate, in the personages marked for good or evil fortune.
Medieval
tragedy arouses pity, but also fear. No telling what Fate holds for us. We are helpless.
Shakaespeare's idea of tragedy is larger than the medieval idea, but includes this viewpoint.
A.C. Bradley
in Shakespearian Tragedy, the plays focus on a tragic hero of high degree who dies at the end. Typically, the play depicts the troubled times of exceptional suffering and calamity leading up to his death. The suffering is of an unexpected and striking sort, in contrast to previous happiness or glory. Because the heroes are of high degree, their fates affect more than themselves (city, nation). Their suffering produces pity in the audience.
Calamities of tragedy proceed from the actions of men--the sequence leads to catastrophe, which is precipitated by the characters. Chance does play a role, but is subordinate to the responsibility which the characters have. In one sense, the action of the play is the expression of the hero's character or personality. He sets the events in motion and then can't control them.
Tragic heroes are exceptional beings, in degree and in nature. They are intensified, presented on a grand scale, their emotions have great force. They have a fatal tendency to identify their whole beings with one interest, object, passion or habit of mind (a