Buddhism of the Khmer
In recent centuries Cambodia has largely been influenced by the Buddhism of the Thai kingdom, centred on the basin of the Chao Phraya river, with its capitals at Ayutthaya and Bangkok. So it is characterized by the presence both of the standard features shared with all forms of southern Buddhism and many local traditions - both those belonging to South-East Asia generally and others which are specific to Cambodia. Noticeable is some continuation of traditional practices which have tended to become partially obsolete in Thailand. At the same time there has been some attempt to introduce the administrative and organizational forms which are a strong element of modern Thai Buddhism, especially in court circles.
Little is known of the early history of Khmer Buddhism, but it seems to have been mainly introduced from Northern India and to have been Sanskrit rather than Pali-based. Chinese sources would suggest that Buddhism was quite influential in the kingdom of Funan in the first half of the millennium A.D. Mahayana Buddhism seems to have been well established at that time. Inscriptions demonstrate that during most of the heyday of the Khmer Empire (from the ninth century) Brahmanical deva cults were predominant at court, but Mahayana Buddhism was adopted during the twelfth century. During the thirteenth century (after the destruction of the major centres of Sanskrit Buddhism in India) forms of southern Buddhism using Pali became influential, although they were certainly already present on a small scale in some Khmer-speaking areas many centuries before this. During the following period and especially after the removal of the capital from Angkor to the region around Phnom-penh in the fifteenth century, other forms of Buddhism and brahmanism gradually declined in influence and largely disappeared, although leaving many traces of their former importance. Khmer Buddhism greatly influenced the Buddhism of Central Thailand in the past and has itself come under strong influence from there in recent centuries. French rule during the earlier part of the twentieth century only slightly weakened Khmer Buddhism and the early period after independence saw a strong element of Buddhist revival. Subsequent Communist rule by the Khmer Rouge led to a short period of severe repression of Buddhist activity, but thereafter Buddhism was allowed to operate a little more freely and is currently showing strong signs of revival.
Those of Southern Buddhism in general.
There are around ten million Khmer Buddhists in Cambodia itself and about two and a half million in neighbouring countries and in the diaspora.