Americans Isadora Duncan and Ruth St. Denis, and German-born Mary Wigman have long been credited with beginning the movement against classical ballet and toward the system of expressive gestures known as modern dance.
Ballet performances had largely been a mode of entertainment. While often employing mythical stories as a structural basis, modern dance became a vehicle for making a statement on current issues.
The late 1930s marked a decidedly new approach to modern dance, one where internal movements such as breathing were the impetuous for dance movements.
Modern dance found the performer in a dual role--choreographer and dancer. This came about in large part because of practicality as the conventions of this type of dance are constantly in a flux of ongoing creation.
After World War II, modern dance experienced a dramatic change. Instead of forsaking traditional technique, modern dance began to employ some ballet and social dance steps, and theory.
Modern dance creates its own conventions, evolving with the era and the narrative structures of the time in which it is being performed. It is a continual agent of change.