The History of Thailand begins with the earliest Bronze and Iron Age sites such as Ban Chiang around 1500 BCE. The region of present-day Thailand was inhabited by indigenous Austroasiatic-speaking groups: the Mon, Lawa, Khmer, and the Austronesian Malay by the 1st millennium. The Kra-Dai-speaking Tai tribes mass migrated from South China to Mainland Southeast Asia between the 8th-10th century. This intensified in the 13th century by pressure of the Mongol armies in China. The Tai tribes settled in northern and central areas like the city-state Lavo. The Tai people assimilated with the indigenous groups and adopted the Dvaravati culture which thrived in the city-states along the Chao Phraya Basin.