It is evident that Chinese ethnic group Han are descendents of Yan and Huang groups—called Hua-Xia tribe. However, recent theories also added Ci-You and other tribes as Chinese Han’s ancestors. The Hmong history suggested that most of old Hmong people were either enslaved, or forced to convert to Hua-Xia (in terms of life style, language, and religion). Anyway, all of them have very similar physical appearance, thus probably mixing pretty well. 

Back to history. After the bloody war between Ci-You and Yan-Huang, old Hmong people fled and settled down along the Yangzi River (Chang Jiang River, the longest river in China), places we now called Three Gorges in Yangzi River. The land was still excellent for planting rice (indeed it is still the major rice base in China now). Hundreds years were past; the old Hmong people were called San-Miao (three feathers, in old time, Miao=Mao, feathers). The name was thought to be derived from the fact that old Hmong people might have three feathers on their hats.

Old Hmong people were again had pretty good time in new place and grew into a big country. It was also thought that San-Miao country was more advanced in agriculture. It was privatelized and had some elements of modern social structure like hierarchy. On the other hand, the Yan-Huang group, now Hua-Xia tribe, was in the hand of Yao, a saint emperor. When Yao was stepping down, he didn’t hand the country to his son, instead, he gave it to Sun, another saint emperor. Legend said that Yao’s son (Dan Zhu) fled to San-Miao and persuaded San-Miao to attack Hua-Xia country. Another war began, and San-Miao was defeated again. It may be conceivable that San-Miao and Hua-Xia would fight anyway because they were neighbors and both of them wanted opponent’s land.

This time, the war ended a little bit differently. Sun, the Hua-Xia emperor, ordered all San-Miao surrenders changed their lifestyle, language, and religion to become Hua-Xia people. Some of them were even relocated to the north-western part of China. They were the ancestors of modern south-western Hmong people in China.

There were some Hmong people fled (again) south into mountains. These people are said to be ancestors of modern southern Hmong people.

Time goes by. Hua-Xia people, now Han ethnic group, kept pushing on. Hmong people kept retreating till all of them were living in high mountains, thus being isolated.

It is somewhat surprising that once an advanced group ended up a primitive group. There are probably several reasons:

First, after being pushed into mountains, great physical barriers not only hindered Han, the invaders, but also made it difficult to interact within themselves. Hmong people were separated into small groups, and gradually lost contact to each other. There are now many Hmong groups living in China and part of Southeast Asia. Their lifestyle and language are different. They can’t understand each other. There is no written Hmong language until 100 years ago.

Second, because Hmong lived in higher altitude than indigenous people, they were hard to see and earned a name “hill dwelling people”. Furthermore, since Hmong people refused to surrender to Han people, they were essentially blocked by Han people. Efforts (mostly brutal) had been tried to “civilize” them but all failed. Therefore, they somewhat lose “opportunity” to catch up with the rest of world.

Finally, even though some Hmong groups settle down in some remote mountain areas and formed a Miao country, it was weak, and frequently defeated by Han people. The life of Hmong people was unstable. They always struggled for basic needs such as food and shelters. Any more advanced developments were impossible.

Nevertheless, it is generally agreed that modern Hmong people are derived from old Miao people. They shared many culture with Chinese Han people, even though they fled from middle land and refused to merge with Chinese Han. They are brave people by all means.