The first and strongest Thai kingdom was Nanzhao in modern Yunnan; they were a threat to the Tang and once pillaged all the way to Chengdu in Sichuan and razed the city. Eventually though the Mongols came and destroyed the kingdom (like almost every other nation they came into contact with). This resulted in a sustained migration to the south.Posted by me
>>The Turks were an older power than the Vietnamese, Spanish, Thai definitely. There were already Turks contolling the Islamic Caliphate in Baghdad (behind the scenes as slave soldiers) before the Mongols came and also the Khorezm Sultanate in Central Asia later (when the Mongols invaded).
The Thai only formed present Thailand after they were driven out of Nanzhao in Yunnan by the Mongols in the 12-13th century AD. The Vietnamese only formed as a nation during one of their dynasties in the 10-11th century AD (forgot name). The Spanish were slightly later, when they began driving the Moors out of Iberia. The Turks already formed their first empire on the steppes of Mongolia in the 6-7th century AD, around the time of the Tang in China.>>
Posted by milty
The Thai may be a case to be argued, but they have settled in Thailand since the 8th century, divided into the Lan Na and the Sukhothai.
Thai tribes might have begun moving south centuries before but they didn't have an impact on the area till the destruction of Nanzhao, other than serving as auxilliaries for the Burmese.

This Thai kingdom was destroyed by the Burmese, not the Khmers. In fact, betw the Vietnamese and the Thais, they were forcing back the Khmers and taking their territories.The Sukhothai was conquered by the Khmers, and Lan Na had much Hmong influence, so they were weak in terms of military power.
The Chinese weren't interested much in SE Asia. Apart fr the Chinese, the Thai could match anyone in the area militarily if necessary. Read more on those Thai-Burmese wars.The redeeming factor for them I feel is that they were able to retain their own culture and Buddhism as a religion even with all these strong pressures on their borders from Islam, Chinese, and other SE Asian ethnicities who were more adept in warfare.
Military power is also a measure to be used.Thai culture is one of the most unqiue in SE Asia, with elaborate temples and costumes. The Turks on the other hand, is less well known culturally, but was a much larger military power.

