Little is kown about the slow migration, probably from before the eighth cen- tury, of Tai peoples from southern China into northern Vietnam, Laos, and Burma (now Myanmar). It may have been, however, partly in response to Chinese attempts to tighten their administrative control over minority peoples in southern China (Wyatt 1984). Their movement would have been slow, from one river valley to the next as population expanded and land could be wrested from whoever was already there. Partly the process would have been peaceful: Tai farmers taking up vacant land along valley floors, laboriously constructing their rice fields and irrigation channels, intermingling with people already there, speaking Austroasiatic languages, and farming rain-de- pendent rice supplemented by hunting and gathering of forest products. At first, the Tai speakers were probably partly dependent on these neighbors (Khmu, Lamet) for food and assistance. But, as their numbers grew, conflict must have at times occurred. Eventually, their superior political organization would have enabled the Tai to take control of the valley and force the earlier inhabitants to move to higher ground.