Buddhism has been the dominant religion in Cambodia, in one form or another, since the reign ofJayavarman VII (c. 1181-1200). Before its adoption as the state religion however, Hinduism flourished for over a thousand years. Roman Catholicism was introduced by French missionaries beginning in the eighteenth century. Sunni Islam is practiced among the Chams, while among the Sino-Khmer population Mahayana Buddhism, Confucianism and Chinese folk religions remain popular.
Buddhism has existed in Cambodia since at least the 5th century AD, with some sources placing its origin as early as the 3rd century BC. Theravada Buddhism has been the Cambodian state religion since the 13th century AD (excepting the Khmer Rouge period), and is currently estimated to be the faith of 95% of the population.
The history of Buddhism in Cambodia spans nearly two thousand years, across a number of successive kingdoms and empires. Buddhism entered Cambodia through two different streams. The earliest forms of Buddhism, along with Hindu influences, entered the Funan kingdom with Hindu merchants. In later history, a second stream of Buddhism entered Khmer culture during the Angkor empire when Cambodia absorbed the various Buddhist traditions of the Monkingdoms of Dvaravati and Haripunchai.
For the first thousand years of Khmer history, Cambodia was ruled by a series of Hindu kings with an occasional Buddhist king, such as Jayavarman I of Funan, and Suryvarman I. A variety of Buddhist traditions co-existed peacefully throughout Cambodian lands, under the tolerant auspices of Hindu kings and the neighboring Mon-Theravada kingdoms.