Border warfare between the Chinese and the…

Border warfare between the Chinese and the Xiongnu is almost incessant during the next century, as Chinese strength wanes.

Gradually the nomads force their way back into Gansu and the northern part of what is now China's Xinjiang-Uygur Autonomous Region.

In about the middle of the first century CE, a revitalized Eastern Han Dynasty (CE 25-220) slowly recovers these territories, driving the Xiongnu back into the Altai Mountains and the steppes north of the Gobi.

During the late first century CE, having reestablished the administrative control over southern China and northern Vietnam that had been lost briefly at beginning of this same century, the Eastern Han make a concerted effort to reassert dominance over Inner Asia.

A Chinese army crosses the Pamir Mountains, conquers territories as far west as the Caspian Sea, defeats the Yuezhi Kushan Empire, and even sends an emissary in search of the eastern provinces of Rome.