Northern Thailand, which has a history largely independent from the rest of the country, appears to have been populated by different groups of Thais, who assimilated with local inhabitants and settled in the fertile valleys of the north around the first millennium. Present-day Chiang Saen was the seat of the Ngong Yang kingdom, and was one of the main centers. Chiang Saen and Payao, another center, were both in contact with India, through Burma, and traded with the Srivijaya empire. The decline of the latter led to the emergence of a trade route to Chaina and ultimately to the birth of a powerful kingdom in the north.
