History of Mongolia
Although the Xiongnu finally had been split into two parts in AD 48, the Xianbei (or Hsien-pei in Wade–Giles) had moved (apparently from the east) into the region vacated by the Xiongnu. The Xianbei were the northern branch of the Donghu (or Tung Hu, the Eastern Hu), a proto-Mongol group mentioned in Chinese histories as existing as early as the 4th century BC. The language of the Donghu is believed to be proto-Mongolic to modern scholars. The Donghu were among the first peoples conquered by the Xiongnu. Once the Xiongnu state weakened, however, the Donghu rebelled. By the 1st century AD, two major subdivisions of the Donghu had developed: the proto-Mongolic Xianbei in the north and the Wuhuan in the south.
Han–Xiongnu War
In 67 BC, the Han empire gained absolute control over the Turfan Depression after inflicting a significant defeat to the Xiongnu. During the former Xiongnu rule of the Western Regions, the area was under the jurisdiction of the Rizhu King (日逐王) with the office "Commandant in
Charge of Slaves". However, in 60 BC, the Rizhu King surrendered to Protector General Zheng Ji. Afterwards (60 BC), the Han imperial court established the Protectorate of the Western Regions. The Han empire, now in absolute control of the Western Regions, placed it under the jurisdiction of its Protector General. As its dominance of the area was established, the Han were effectively controlling the trade and shaping the early history of what would be known as the Silk Road.