Noble graveyards of the Tuyuhun people in Gansu province portrayed a prosperous culture through unearthed silk pieces, gold and silver artifacts and other items. The largest number of Tang Dynasty letters ever found at one time, from the Kiyakkuduk beacon towers site in the Xinjiang Uygur autonomous region, not only demonstrated border guards' nostalgia for home and dedication to the country, but also helped fill gaps in historical studies.