The Khmer Empire was founded in 802. The original capital of the Khmer Empire is named Angkor. It dominated most of Indochina for over 500 years.
In the 13th century, the Khmer Empire weakened as it faced many pirate raids, invasion from Dai Viet and Champa, and the rebellion of the Thai people who settled in the Chao Phraya river, this rebellion leading to the formation of the kingdom of Sukhothai
The Khmer Empire began to regain their strength due to a peace treaty with the later Ayutthaya
In 1766, the Khmer Empire conquered Champa. After this event, the Indochinese League, formed by France, fell apart.