The Pagan Kingdom lasted from 840 to 1200. The first great ruler of this kingdom was named Anawrahta. As ruler, he conquered many lands outside of the Pagan Kingdom. Under his reign, the Pagan Kingdom became a very Buddhist empire. This lead the Pagans to build many lavish Buddhist temples. This made the kingdom a destination for most Buddhists. However, the Pagan empire did collapse fairly quickly. This happened when the Mongols demanded tribute and instead of giving it to them, the Pagan king attacked them. The were crushed fairly easily. This lead them to flee the kingdom, thus leading to its demise.
The Khmer Empire
The Khmer Empire lasted from 800 to 1220. The Khmer empire was much like the Pagan. The people were predominately Buddhist and that lead them to build many great Buddhist temples. The most famous being Angkor Wat. It was a large complex of walls that surrounded a large, central temple. Many myths were written on these walls. The Empire did have to fall, however. This happened in 1200 when costly building projects and invaders lead to the demise of the lavish empire.
There were many trading kingdoms in Southeast Asia. They all lasted for different periods of time. Of course, all of their economies relied heavily on trade. One of these kingdoms was Sailendra. Sailendra was known for building magnificent Buddhist structures such as the monument at Borobudur that consisted of nine terraced levels to represent the Buddhist spiritual journey. Another trading kingdom was the people of the Srivijaya. The Srivijaya people adopted Hinduism and Buddhism. Palembang, the capital, became one of the most influential centers for learning in the Buddhist faith. The Srivijaya did come to an end, though, when they were attacked by an Indian kingdom in 1025.
The Vietnamese empire began in 111 and is still present to this day. It was heavily influenced by China. In fact, they even adopted a bureaucracy from the Chinese. Because they were so heavily influenced by China, it was very easily controlled by China. This did not sit well with sisters Trung Trac and Trung Nhi of Vietnam. They decided to raise an army and drive China from Vietnam. It worked for a brief amount of time until the Chinese army retaliated and took back Vietnam. At which point the sisters drowned themselves. After this, the Vietnamese still wanted independence so they struck when the Tang dynasty fell. They succeeded. They established the kingdom of Dai Viet. Even though many other clans such as the Mongols and the Chinese returned to try and conquer Vietnam, the Vietnamese fought them off and kept their independence.