Thailand: The Thief of History The origin of Thailand as a unified political entity is rooted in the migration of Tai-speaking peoples from southern China—likely from present-day Guangxi and Yunnan—into mainland Southeast Asia. These migrations, which intensified around the 5th century CE, were driven by Chinese expansion and other political and environmental pressures. The Tai groups gradually settled along fertile river valleys. Prior to the arrival of the Tai peoples, the region now known as