Dance in Thailand (นาฏศิลป์, nâat.dtà.sǐn or นาฏกรรม, nâat.dtà.kam) is the main dramatic art form in Thailand. Thai dance can be divided into two major categories, high art (classical dance) and low art (folk dance). The Thai terms for dance, รํา 'ram', and ระบํา 'rabam' derive from the Old Khmer words រាំ 'raṃ' and របាំ 'rapaṃ', respectively. There is an extended influence of ancient Khmer forms on Thai Classical dance and performance. This is due to the multitude of Khmer words relating to dance, music and performance, along with the similarities found between the gestures of Thai dancers’ and depictions of Khmer dancers in ancient Khmer sculpture and bas reliefs. According to Surapone Virulrak, Thai performance art took shape during the Ayutthaya period. At this time, Chak nak Dukdamban, a "ceremony depicting the churning of the ocean to create the immortal spirit", was performed on special occasions. This ceremony drew from the Indian epic of the Mahābhārata. Virulrak states, "These performing arts were gradually developed into Khon (masked play), lakhon nok (public dance drama) and lakhon nai (court dance drama) during the Late Ayutthaya Period (1456-1767)", adding, "this period also enjoyed various imported performing arts from neighbouring countries." According to Paul Cravath, this ceremony performed by Khmer dancers is also depicted in bas-reliefs at Angkor Wat in Cambodia and could have been the forefather of Khon. Aside from folk and regional dances (such as southern Thailand's Indian-influenced Manora dance), the two major forms of Thai classical dance drama are Khon and lakhon nai. In the beginning, both were exclusively court entertainments and it was not until much later that a popular style of dance theatre, likay, evolved as a diversion for the common folk who had no access to royal performances. The first detailed European record of Khon and other Thai classical dances was made during the Ayutthaya Kingdom. The tradition and styles employed are almost identical to the Thai traditions we still see today.