The Thai people are of the Tai ethnic group, characterised by common linguistic roots. Chinese chronicles first mention the Tai peoples in the 6th century BCE. While there are many assumptions regarding the origin of Tai peoples, David K. Wyatt, a historian of Thailand, argued that their ancestors which at the present inhabit Laos, Thailand, Myanmar, India, and China came from the Điện Biên Phủ area between the 5th and the 8th century. Thai people began migrating into present-day Thailand around the 11th century, which Mon and Khmer people occupied at the time. Thus Thai culture was influenced by Indian, Mon, and Khmer cultures.