Expressionism was the major literary and art form in Germany beginning in the early 20th century. It flourished before and during World War I and continued to be the dominant art for of the Early Weimar Republic. By 1924, Neue Sachlichkeit replaced Expressionism as the dominant art form in Germany. Many Expressionists claimed they were never truly apart of Expressionism. However, in the periodization and canonization many of these young artists are labeled as Expressionist. This thesis examines the periodization and canonization of Expression in art, drama, and film and proves that Expressionism began much earlier than scholars believe and ended much later than 1924. This thesis examines the conflicts in Germany that led to Expressionism and which authors and artists influenced Expressionists. It will also show that after Expressionism ceased to be the dominant art form in Germany, many former Expressionists continued to use expressionistic form in their works but ceased to use expressionistic content. This thesis argues that both the periodization and canonization of Expressionism should be expanded to include all works that may be classified as having expressionistic form.