Modern dance is a broad genre of western concert or theatrical dance which included dance styles such as ballet, folk, ethnic, religious, and social dancing; and primarily arose out of Europe and the United States in the late 19th and early 20th centuries. It was considered to have been developed as a rejection of, or rebellion against, classical ballet, and also a way to express social concerns like socioeconomic and cultural factors.
In the late 19th century, modern dance artists such as Isadora Duncan, Maud Allan, and Loie Fuller were pioneering new forms and practices in what is now called improvisational or free dance. These dancers disregarded ballet's strict movement vocabulary (the particular, limited set of movements that were considered proper to ballet) and stopped wearing corsets and pointe shoes in the search for greater freedom of movement.
Throughout the 20th century, sociopolitical concerns, major historical events, and the development of other art forms contributed to the continued development of modern dance in the United States and Europe. Moving into the 1960s, new ideas about dance began to emerge as a response to earlier dance forms and to social changes. Eventually, postmodern dance artists would reject the formalism of modern dance, and include elements such as performance art, contact improvisation, release technique, and improvisation.
American modern dance can be divided (roughly) into three periods or eras. In the Early Modern period ( 1880–1923), characterized by the work of Isadora Duncan, Loie Fuller, Ruth St. Denis, Ted Shawn, and Eleanor King, artistic practice changed radically, but clearly distinct modern dance techniques had not yet emerged. In the Central Modern period ( 1923–1946), choreographers Martha Graham, Doris Humphrey, Katherine Dunham, Charles Weidman, and Lester Horton sought to develop distinctively American movement styles and vocabularies, and developed clearly defined and recognizable dance training systems.