The Natya Shastra, written by Bharatha between second century BC and second century AD, is the source of all forms of Indian classical dance. It is regarded as the fifth Veda. Brahma, the supreme Creator, is believed to have created Natya by taking literature from the Rig Veda, songs from Sam Veda, abhinaya or expression from Yajur Veda and rasa or aesthetic experience from Atharva Veda. It speaks in great detail of the different kinds of postures, facial expressions, mudra or hand expressions, and the attire and ornaments to be used. All dance forms are structured around the nine rasa or emotions.
All dance forms follow the same hand movements, with variation creeping in due to local demands.
The uniqueness of Indian classical dances is that they are all devotional in content. In fact Bharata Natyam was till the early 20th century, only performed by 'devadasis' or maids of God, in temples. Folk dances have gained more popularity, as they are easier to understand and perform. They do not require the skill and expertise of a classical dance performer. They are performed by the rural folk and are extremely enjoyable.