 In the second century BCE the region became part of the Xiongnu empire, a confederation of nomads centered on present-day Mongolia.The Tarim Basin was first referred to as "Xiyu" () under the Han dynasty, which drove the Xiongnu out of the Tarim Basin in 60 BCE (Han–Xiongnu War) in an effort to build and secure the profitable Silk Road, maintaining a variable military presence until the early 3rd century CE.From the 2nd to the 5th century local rulers controlled the region.