From 304 AD to 439 AD (from the first year of Yongxing in the Western Jin Dynasty to the unification of the Northern Wei Dynasty), sixteen separatist regimes were established successively from the Huaihe River in the south to the present, Yinshan Mountain in the north, Qinling Mountain in the west, the East China Sea in the east, the lower reaches of the Yalu River in the northeast and Lancang River in the southwest. That is, Cheng () and Han (Xiongnu) established during the Yongxing period of the Western Jin Dynasty, and (Xiongnu), Hou Zhao (Jie Li), (Han), (Xianbei), Qian Qin (Bian), Hou Qin (Qiang) and Hou Yan (Xianbei) established after the demise of the Western Jin Dynasty. In addition, there are (Han) and, but they are not included. Han and former Zhao were merged into one country, which is called the Sixteen Kingdoms Period. The five main tribes that entered the Central Plains, namely Xiongnu, Anta, Xianbei, Bianyi and Qiang, were called Wuhu in history. Known as the five colors and sixteen countries. Be unified by the Northern Wei Dynasty