The Khmer Empire was a major southeast asian empire and existed from 802 ad to 1431. This is basically the "Cambodian Empire". It was founded by the last king of the Chenla Kingdom. The Khmer Empire expanded and became legendary for its architecture, especially temples and wealth. Eventually, Angkor was built and was made the capital of the empire. Even later, the Khmers became corrupt and the Thai Ayutthaya kingdom sacked the empire and destroyed its cities. This started the Cambodian Dark Ages and lasted until French Colonization in the late 1700s-1800s.