Even before the ancient Greeks were performing the works of Aeschylus and Sophocles, there was drama. Religious rituals and folk celebrations across the world have elements of the theatrical. They are the deep roots of drama.
Aristotle broke drama down into six elements: character, ideas, language, action (plot), music, and spectacle. Aristotle also wrote about catharsis, the purging of emotion, as part of drama.
Drama is often represented by masks of tragedy and comedy. Tragedy and comedy share many qualities. Both involve conflict, but the way that conflict is resolved is different. Traditionally, tragedy ends in the death of the main character or characters, while comedy ends with celebration or marriage.
There are many sub-genres of tragedy and comedy, and sometimes the two are mixed together. Dramady, situation comedy, farce, theater of the absurd, melodrama, courtroom drama and satire are a sampling of the types of drama.
The Globe theatre, which put on many of Shakespeare's plays, opened in 1599. The Elizabethan period, when Elizabeth I ruled England from 1558 to 1603, saw people going to plays in large numbers.
Modern drama can be divided into two main categories---realism and expressionism. Realism concentrates on the details of daily life. Expressionism is more concerned with feelings and uses innovative techniques to express the interior lives of characters.