The history of Cambodia, a country in mainland South East Asia can be traced back to at least the 5th millennium BC..Centered around the lower Mekong, it traded with partners in the Indosphere. The Khmer empire was established by the early 9th century. Sources refer to a mythical initation and consecration ceremony to proclaim Jayavarman II at Mount Kulen to be King of all Cambodia around 802 C.E.
For 2,000 years Cambodia’s civilization absorbed influences from India and China and, in turn, transferred them to other Southeast Asian civilizations. From the Hindu-Buddhist kingdoms of Funan and Chenla (1st-8th century) through the classical age of the Angkor period (9th-15th century it held sway over territories that are now part of Thailand, Vietnam, and Laos.
At the apex of its powers, around the 12th century, the construction of Angkor Wat and Bayon were constructed. Due to unknown circumstances, the Kingdom decline over the next 400 years.