Chenla
The people of Chenla were Khmer and wrote in Khmer script, as opposed to the Funan practice of writing in Sanskrit. Chenla is first mentioned in the Chinese Sui History as a Funan vassal. The founder of the kingdom, who managed to break free from Funan's control, was Strutavarman. A later king, Bhavarman, invaded Funan annexing it to Chenla's domains. Once they established control over Funan, they embarked on a course of conquest that continued for three centuries. They subjugated central and upper Laos, annexed portions of the Mekong Delta, and brought what are now western Cambodia and southern Thailand under their direct control.
At the same time, king Mahendravarman established peace with the neighboring kingdom of Champa through marriage arrangements, and Isnavarman, who succeeded him in 616, moved to a new capital, which, according to a Chinese writer, was inhabited by 20 thousands families. Culturally, the royal families of Chenla generally preserved the earlier political, social, and religious institutions of Funan, thus preserving the elements introduced from India. Chenla appears to have had a preference for Hinduism over other religions brought from there, like Buddhism.
In the 8th century, however, factional disputes at the Chenla court resulted in the splitting of the kingdom into rival northern and southern halves. According to Chinese chronicles, the two parts were known as Land (or Upper) Chenla and Water (or Lower) Chenla. Land Chenla maintained a relatively stable existence, but Water Chenla underwent a period of constant turbulence, partly because of attacks from the sea by the Javanese and others. The Sailendra dynasty in Java actively tried to establish control on Water Chenla territories and eventually forced the kingdom to vassal status. The last of the Water Chenla kings allegedly was killed around 790 by a Javanese monarch whom he had offended. The ultimate victor in the strife that followed was the ruler of a small Khmer state located north of the Mekong Delta. His assumption of the throne as Jayavarman II (ca. 802 - 850) marked the liberation of the Khmer people from Javanese suzerainty and the beginning of a Khmer empire.
Read more about this topic: Early History Of Cambodia