Expressionism is a modernist movement in drama and theatre that developed in Europe (principally Germany) in the early decades of the 20th century and later in the United States. It forms part of the broader movement of Expressionism in the arts.
There was a concentrated Expressionist movement in early 20th century German theatre of which Georg Kaiser and Ernst Toller were the most famous playwrights. Other notable Expressionist dramatists included Reinhard Sorge, Walter Hasenclever, Hans Henny Jahnn, and Arnolt Bronnen. They looked back to Swedish playwright August Strindberg and German actor and dramatist Frank Wedekind as precursors of their dramaturgical experiments.
Oskar Kokoschka's Murderer, the Hope of Women was the first fully Expressionist work for the theatre, which opened on 4 July 1909 in Vienna. In it, an unnamed man and woman struggle for dominance. The Man brands the woman; she stabs and imprisons him. He frees himself and she falls dead at his touch. As the play ends, he slaughters all around him (in the words of the text) "like mosquitoes." The extreme simplification of characters to mythic types, choral effects, declamatory dialogue and heightened intensity would become characteristic of later Expressionist plays. The first full-length Expressionist play was The Son by Walter Hasenclever, which was published in 1914 and first performed in 1916.
In the 1920s, Expressionism enjoyed a brief period of popularity in the theatre of the United States, including plays by Eugene O'Neill (The Hairy Ape, The Emperor Jones and The Great God Brown), Sophie Treadwell (Machinal), Lajos Egri (Rapid Transit) and Elmer Rice (The Adding Machine).
Expressionist plays often dramatise the spiritual awakening and sufferings of their protagonists and are referred to as Stationendramen (station dramas), modeled on the episodic presentation of the suffering and death of Jesus in the Stations of the Cross. August Strindberg had pioneered this form with his autobiographical trilogy To Damascus (1898-1904). Early expressionism in particular testified to the failure of social values with a predilection for ecstasy and despair and hence a tendency towards the inflated and the grotesque; a mystical, even religious element with frequent apocalyptic overtones; an urgent sense of the here and now.
The plays often dramatise the struggle against bourgeois values and established authority, often personified in the figure of the Father. In Reinhard Sorge's The Beggar (Der Bettler), the young hero's mentally ill father raves about the prospect of mining the riches of Mars and is eventually poisoned by his son. In Arnolt Bronnen's Parricide (Vatermord), the son stabs his tyrannical father to death, only to have to fend off the frenzied sexual overtures of his mother. In Expressionist drama, the speech is heightened, whether expansive and rhapsodic, or clipped and telegraphic. Director Leopold Jessner became famous for his Expressionistic productions, often unfolding on stark, steeply raked flights of stairs (an idea originally developed by Edward Gordon Craig), which quickly became his trademark.
Expressionism in the theatre can be broken down into three categories. Geist performance was an abstract form that was completely spiritual avoiding complex plot structures and psychologically involved characters. Schrei or 'scream' performance was at the highest point of human emotion. Raw, dark and intense—this conveyed the image of a nightmare, time was non-existent and characters were warped. This often followed the struggle of an unnamed individual man who was a symbol for the darkest plights of humans. The Cabinet of Dr. Caligari is a perfect example of this style of performance—actors are often animalistic and relentless in their discharge of energy. The Ich 'ego' style focused on a central characters struggle against the world. This individual may have been the most grotesque or the least grotesque and interacts with 'bodies of people' rather than other individuals. Bodies of individuals may represent larger concepts/institution like 'industry' for example. The actors would perform in unison often with mechanical and monotonous movements. In all instances emotions were heightened and characters were grotesque as Sokel asserts when quoting Edschmid 'the sick man is not just the cripple who suffers. He becomes sickness itself' 
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