Did the ancestors of Thailand come from China?

The ancestors of Thais all came from the south of China, including Siam.

Luo, Lao and China people. In history, due to nomads heading south, Han people fled to the south in succession, squeezing the living space of southerners. The southern nationalities had to migrate further to the south. Thai descent and language are close to those of Zhuang, Buyi and Dai in southern China, and Thai people were introduced into Buddhism before Han people in China. Therefore, Thai customs are more influenced by ancient India than China. The migration of China people (southern Han people) to Thailand can be traced back to the Song Dynasty at the earliest, but the large-scale migration was in the Ming Dynasty and later.

It is also said that China people immigrated to Thailand in large numbers in modern times, and the Thai royal family also had China descent, but their ancestors had little to do with China.