The cultures of insular Southeast Asia are made up predominantly of peoples speaking Austronesian languages, and the traditional religions of the area, despite substantial diversity and extensive borrowing from other sources, retain significant features that reflect a common origin. Linguistic evidence indicates that the point of origin of the languages of present-day Austronesians was the island of Taiwan (Formosa) and possibly also the adjacent coastal region of southeastern China. The initial expansion of the Austronesians began in the third millennium BCE and proceeded, by stages, through the Philippines and the islands of Indonesia, then east to the islands of the Pacific, and eventually west as far as the island of Madagascar.

In the first stage of this expansion, migrating Austronesian groups possessed a basic cultural technology that included the domesticated dog and pig, a knowledge of the cultivation of rice, millet, and sugarcane, and a developing...