Pagan Kingdom: AD 840
The first great king was Anawrahta. He conquered many areas around him. Because of all his counquerings they had trading ports all over the place. Their government was an monarchy. Most of the Pagan Kingdom were Buddhists. THey built many great temples. Pagan was the center for Buddhist learning.
Khmer Empire: 800
They adopted both Hinduism and Buddhism. They government was an absolute Monarchy. They had an agricultural economy, and the government was based on agriculture. There are so many great temples, some still standing today that were built during the Khmer age.
The kingdom brought in Mahayana Buddhism. They basically adopted all of the Buddhist culture. The Capitals were, Mali, Ghannan, and Songhai. They were mostly known for their gold export.
Vietnam had an agricultural economic base. Confucianism and Daosim were both used in Vietnamese culture. They also had a bureaucracy government. China changed lots of their beliefs but they still kept some and preserved them.