 Parts of southern Xinjiang were controlled by the Tuyuhun Kingdom (284–670), who established a vast empire that encompassed Qinghai, Gansu, Ningxia, northern Sichuan, eastern Shaanxi, southern Xinjiang, and most of Tibet, stretching 1,500 kilometers from east to west and 1,000 kilometers from north to south.They unified parts of Inner Asia for the first time in history, developed the southern route of the Silk Road, and promoted cultural exchange between the eastern and western territories, dominating the northwest for more than three and half centuries until it was destroyed by the Tibetan Empire.The Tuyuhun Empire existed as an independent kingdom outside China and was not included as part of Chinese historiography.