East Turkistan is the Historical Homeland of Uyghurs

You raised a very important question that we would like to answer. Present day "Xinjiang " has always been the homeland of Uyghurs since ancient times. The following historical evidence prove this. The land which is called Xinjiang by the Chinese Government was inhabited and ruled by the Saks, the Huns and the Turks at different times of the history, who are the ancestors of Uyghurs. After the demise of Great(Kok) Turk Empire that stretched from present day Mongolia to Black Sea, a new Turkic Nation appeared in the land from Mongolia to Aral Sea in 744 AD, which was called Uyghur State. Although the name and the ruling class of the state was different, the inhabitants of that land were the same. At that time the present day Mongolia was the political center of Uyghurs and other Turkic people. The inhabitants of Central Asia, which was part of that state, were also Uyghurs and other Turkic people as well.

In 840 AD, Uyghur state was disintegrated because of the internal power struggle in the Palace, widespread drought and deadly epidemic which claimed hundreds of thousands of lives. Uyghurs were not chased out of their homeland, but they simply moved their political and economic center from the east of the state to the west. That is true that the king was chased by the forces who were opposing him with the help of Kirgiz and other tribes. Most of the people moved out because of epidemic, drought and civil war. After ten years, The Uyghur State was disintegrated into three states. They were Idikut Uyghur Kingdom that was centered around Turpan, Karahanidin Kingdom that centered around Kashgar, and Kansu Uyghur Kingdom centered around Hexi Corridor. Pantekin, the first king of the Idikut Uyghur State was the younger brother of the former Uyghur States'King. The movement of the people at that time was merely an internal migration.

I hope this is helpful.You are more than welcome to raise any further question on this matter.