Milton's fourth invocation differs from earlier ones in that he does not call on Urania, except obliquely, and he does not mention his blindness. Rather he offers an explanation for his epic and says that the tone must now become "Tragic" (6). The word "tragic" had two connotations for Milton. First, it carried the simple moral meaning of something terribly bad or unfortunate. Christians since the Middle Ages had always considered the falls of Lucifer and Adam tragic. But "tragic' also refers to the dramatic concept of tragedy as first defined by Aristotle and developed through the centuries to its high achievement in Elizabethan England. Milton knew the nature of dramatic tragedy from his study of the Greeks (he patterned Samson Agonistes on Greek tragedy) as well as from reading Shakespeare and other Elizabethan dramatists (he wrote an essay On Shakespeare for the Second Folio).
By the seventeenth century, tragedies had assumed a basic format. The play would have a noble hero who had a tragic flaw in either personality or actions. The fortunes of the hero would reverse during the play from good to bad with the hero recognizing his own responsibility for these consequences that resulted from his flaw. The end of the play would result in the death of the hero. Throughout the play, fate would, in one form or another, control the action, and, at the end, the audience would experience a catharsis or purging of emotions, resulting from their empathy with the hero. They should feel pity for the hero and fear for themselves.
