URUMQI, China — The Loulan Beauty is one of more than 200 remarkably well-preserved mummies discovered in the western deserts here over the last few decades. The ancient bodies have become protagonists in a very contemporary political dispute over who should control the Xinjiang Uighur Autonomous Region.

The Chinese authorities here face an intermittent separatist movement of nationalist Uighurs, a Turkic-speaking Muslim people who number nine million in Xinjiang.

At the heart of the matter lie these questions: Who first settled this inhospitable part of western China? And for how long has the oil-rich region been part of the Chinese empire?

Uighur nationalists have gleaned evidence from the mummies, whose corpses span thousands of years, to support historical claims to the region.