A little bit of History..

Bharatanatyam is a classical dance form originated in the state of Tamil Nadu in South India. It is one of the oldest Indian dance forms, has a tradition of more then 2000 years. It is said to be performed in temples by Devadasis (women dedicated to serve the lord) in ancient times. Many of the ancient sculptures in Hindu temples are based on Bharatanatyam dance postures.

Bharatanatyam is also thought to have been created by the Bharata Muni, a Hindu sage, who wrote the Natya Shastra, the most important ancient treatise on classical India, which describes everything from Classical Dance, Music, stage craft, literature and fine arts of India.

The two hundred year colonial rule in India brought massive changes to the society and the Arts and everything else Indian. In the westerners' eyes, the Devadasi tradition was considered little better than prostitution, and thus treated; it was inevitable that it fell into disrepute. The medieval Rajas (Rulers of kingdoms) gave less Patronage to the art form and used the dance as entertainment. The classical science of dance was ignored. At that time a dancer was considered a woman of ill repute.
By the 1930s however, the rising national consciousness that had awakened across India led to reformation not only in the social, but also in the cultural spheres. Rukmini Devi Arundale of Kalakshetra and E. Krishna Iyer are one of the few who purified and raised the social status of the dance form. It is now respected and performed on stage by both men and women.

Bharatanatyam is traditionally performed on Carnatic music (South Indian Classical) and both together are deeply grounded in Bhakti tradition (devotion).

Bharatanatyam dancers now have now taken this dance form to new heights with their creativity and included it in contemporary and modern Indian choreography.

Bibliography:
wikipedia.org
geetachandran.tripod.com