The Northern Silk Road is a prehistoric trackway in northern China originating in the early capital of Xi'an and extending north of the Taklamakan Desert to reach the ancient kingdoms of Parthia, Bactria and eventually Persia and Rome. It is the northern-most branch of several Silk Roads providing trade, military movements and cultural exchange between China and the west. The use of this route was expanded pursuant to actions by the Han Dynasty in the latter part of the first millennium BC to push back northern tribes and control the safe passage of Chinese troops and merchants.