Modern dance is a dance form developed in the early 20th century. Although the term Modern dances has also been applied to a category of 20th Century ballroom dances, Modern dance as a term usually refers to 20th century concert dance. In the early 1900s a few dancers in Europe started to rebel against the rigid constraints of Classical Ballet. Shedding classical ballet technique, costume and shoes these early modern dance pioneers practiced free dance.
— wikipedia