|Pre-Angkorian and Angkorian polities|
During the 3rd, 4th, and 5th centuries, the Indianised states of Funan and Chenla coalesced in what is now present-day Cambodia and southwestern Vietnam. These states are assumed by most scholars to have been Khmer. For more than 2,000 years, Cambodia absorbed influences from India and China passing them on to other Southeast Asian civilisations that are now Thailand, Vietnam, and Laos.
The Khmer Empire flourished in the area from the 9th to the 13th century. Around the 13th century, Theravada Buddhism was introduced to the area through monks from Sri Lanka. From then on Theravada Buddhism grew and eventually became the most popular religion. The Khmer Empire declined yet remained powerful in the region until the 15th century. The empire's centre of power was Angkor, where a series of capitals was constructed during the empire's zenith. Angkor could have supported a population of up to one million people. Angkor, the world's largest pre-industrial civilization, and Angkor Wat, the most famous and best-preserved religious temple at the site, are reminders of Cambodia's past as a major regional power.
Dark ages of Cambodia
After a long series of wars with neighbouring kingdoms, Angkor was sacked by the Thai and abandoned in 1432 because of ecological failure and infrastructure breakdown. The court moved the Capital to Lovek where the kingdom sought to regain its glory through maritime trade. The attempt was short-lived, however, as continued wars with the Thai and Vietnamese resulted in the loss of more territory and Lovek was conquered in 1594. During the next three centuries, the Khmer kingdom alternated as a vassal state of the Thai and Vietnamese kings, with short-lived periods of relative independence between.