section_path: History/Pre-Angkorian, Angkorian, and Post-Angkor
section_name: Pre-Angkorian, Angkorian, and Post-Angkor
paragraph_text: Pre-Angkorian, Angkorian, and Post-Angkor
  
  During the 3rd, 4th, and 5th centuries, the Indianised states of Funan and its successor, Chenla, coalesced in what later is Cambodia and southwestern Vietnam. For more than 2,000 years, what was to become Cambodia absorbed influences from India, passing them on to other Southeast Asian civilisations that later became Thailand and Laos.
  
  The Khmer Empire grew out of the remnants of Chenla, becoming firmly established in 802 when Jayavarman II (reigned c. 790 – c. 835) declared independence from Java and proclaimed themselves a Devaraja. They and their followers instituted the cult of the God-king and began a series of conquests that formed an empire which flourished in the area from the 9th to the 15th centuries. During the rule of Jayavarman VIII the Angkor empire was attacked by the Mongol army of Kublai Khan; the king was able to buy peace. Around the 13th century, Theravada missionaries from Sri Lanka reintroduced Theravada Buddhism to Southeast Asia, having sent missionaries previously in the 1190s. The religion spread and eventually displaced Hinduism and Mahayana Buddhism as the popular religion of Angkor; it was not the official state religion until 1295 when Indravarman III took power.
  
  The Khmer Empire was Southeast Asia's largest empire during the 12th century. The empire's centre of power was Angkor, where a series of capitals were constructed during the empire's zenith. In 2007 an international team of researchers using satellite photographs and other modern techniques concluded that Angkor had been the largest pre-industrial city in the world with an urban sprawl of 2,980 square kilometres (1,151 square miles). The city could have supported a population of up to 1 million people.
  
  After a series of wars with neighbouring kingdoms, Angkor was sacked by the Ayutthaya Kingdom and abandoned in 1432 because of ecological failure and infrastructure breakdown.
  
  The hill tribe people were "hunted incessantly and carried off as slaves by the Siamese (Thai), the Annamites (Vietnamese), and the Cambodians".
  
  Formerly part of the Khmer Empire, the Mekong Delta had been controlled by the Vietnamese since 1698, with King Chey Chettha II granting the Vietnamese permission to settle in the area decades before.