QAPQAL XIBE AUTONOMOUS COUNTY, China — Loyal to the core and prized for their horsemanship, several thousand Manchu soldiers heeded the emperor’s call and, with families and livestock in tow, embarked in 1764 on a trek that took them from northeastern China to the most distant fringes of the Qing dynasty empire, the Central Asian lands now known as Xinjiang.

It was an arduous, 18-month journey, but there was one consolation: After completing their mission of pacifying the western frontier, the troops would be allowed to take their families home.

“They were terribly homesick here and dreamed of one day going back east,” said Tong Hao, 56, a descendant of the settlers, from the Xibe branch of the Manchus, who arrived here emaciated and exhausted. “But sadly, it was not to be.”