One of the most beautiful theatrical spectacles that a person can witness in Asia is the Preah Thong Boung Soung, a rendition of the story of Preah Thong and Neang Neak that is performed by the Royal Ballet of Cambodia. With elaborate costumes, gentle music and exquisite dance, the opera depicts the story that every single child in Cambodia is told at a very young age – the saga of an Indian prince and a serpent (Naga) woman who are the ancestors of all Khmer people.
Like the Indian epic Ramayana, there are several versions of the story of Preah Thong and Neang Neak. One of the most popular versions goes like this: Thousands of years ago, Cambodia was a small island called Kouk Thlouk, meaning the land of the Thlouk tree, a Cambodian species of Chrysobalanaceae. The island belonged to the Nagas (serpents) who lived in the ocean. One day, Naga princess Soma and her subjects transformed themselves into beautiful women and came to the island. The same night, an Indian prince named Kaundinya sailed with his followers to the island. The prince saw the Naga princess dancing in the moonlight and fell madly in love with her and asked her to marry him. She agreed under the condition that the Naga king, her father, approve of the marriage.
In full: https://scroll.in/magazine/1010631/the-legend-of-the-indian-prince-who-is-the-forefather-of-all-cambodians