evidence: By 700 BCE, people in what is now Laos were manufacturing iron tools and had cultural and trade contacts with the Chinese and Indians. In the fourth to eighth centuries CE, people on the banks of the Mekong River organized themselves into Muang, walled cities or petty kingdoms. The Muang were ruled by leaders who paid tribute to more powerful states around them. Populations included the Mon people of the Dvaravati kingdom and proto-Khmer peoples, as well as forebears of the "mountain tribes." During this period, animism and Hinduism slowly mixed or gave way to Theravada Buddhism. The 1200s CE saw the arrival of ethnic Tai people, who developed small tribal states centered on semi-divine kings. In 1354, the kingdom of Lan Xang united the area that is now Laos, ruling until 1707, when the kingdom split into three. The successor states were Luang Prabang, Vientiane, and Champasak, all of which were tributaries of Siam. Vientiane also paid tribute to Vietnam. In 1763, the Burmese invaded Laos, also conquering Ayutthaya (in Siam). A Siamese army under Taksin routed the Burmese in 1778, placing what is now Laos under more direct Siamese control.