In 48 AD, Xiongnu was separated into Northern Xiongnu and Southern Xiongnu, this territory was ruled by King Huyan (呼衍王) whom swore allegiance to the Northern Xiongnu.
The division of the Xiongnu tribe in 48 AD resulted in a split between the Northern and Southern Xiongnu, with King Huyan (呼衍王) ruling over the territory that was under his control.