Chapter 18 Section 4 Partial Expansion in the North and Retreat in the South

In the late 2nd century AD, due to the continuous resistance of the Qiang people in the northwest, the Han Dynasty's control over the Northwest region became weaker and weaker, and many administrative regions had to be abolished or withdrawn to the interior.The Xianbei in the north gradually invaded the south, and the southern Huns who immigrated into the fortress were also expanding the scope of their activities.When the Yellow Turban Uprising broke out in the seventh year of Lingdi Guanghe (AD 184), the Eastern Han Dynasty had no time to care about the frontier. The six counties of Shuofang, Shangjun, Beidi, Dingxiang, Yunzhong, and Wuyuan completely gave up. Xihe, Anding and other counties also gave up part of it, roughly retreating to the current line of Sanggan River, Luliang Mountain, Yellow River and Liupan Mountain.The north of this line is known as "Qianghu". In fact, it is inhabited or mixed with various ethnic groups such as Xiongnu, Xianbei, and Qiang. There are also a certain number of Han people staying there. This situation lasted until the end of the Western Jin Dynasty.

Throughout the period of the Sixteen Kingdoms and the Northern Dynasties, although the north was often in war and the territory was very unstable, because the non-Han people who originally lived in the frontier successively occupied all or part of the Yellow River Basin, they separated the territory of the Central Plains Dynasty from their own base areas. Contiguously, some also annexed other northern ethnic groups, so the jurisdiction of the Central Plains regime has expanded compared to the late Eastern Han Dynasty, the Three Kingdoms and the Western Jin Dynasty.For example, the former Yan annexed the Yuwen Department of Xianbei, added the present-Lao Ha River Basin to the northern border, and basically restored the old land of the Western Han Dynasty.After the Northern Wei Dynasty unified the north, and before the Six Towns Uprising in 523, its northern boundary was not only roughly the same as that of the Qin and Han Dynasties, but the Yinshan area reached even further north, controlling the northern foot of the Yinshan Mountain.

The control of the Western Regions was suspended in the late Eastern Han Dynasty, and the Changshifu of the Western Regions was also abandoned from time to time.However, due to the long-term exchanges between the Central Plains and the Western Regions, and the long-term management of the people of the Central Plains in the Western Regions, the connection between the Western Regions and the Central Plains has not been severed.Not only that, but the local government in the Northwest also set up a formal administrative region in the Western Regions for the first time. In 327, Zhang's Qianliang established Gaochang County, which governed the area east of Hala and Zhuoyi in the eastern part of the Turpan Basin in Xinjiang.After that, it went through the former Qin Dynasty, the later Liang Dynasty, and the Western Liang Dynasty, until Beiliang was destroyed by the Northern Wei Dynasty in 439.It is no accident that the first county in the Western Regions was established in the Turpan Basin.This is the channel leading to the Western Regions. It has always been an important place for the management of the Central Plains Dynasty. Since the Western Han Dynasty, Wuji Xiaowei has been stationed here. A large number of Han people moved here to cultivate, and the agriculture has a very good foundation.Therefore, after Beiliang was destroyed, Gaochang County may still exist as an independent Gaochang state for a long time, and it was not destroyed by Tang until 640.

In Lelang County on the Korean Peninsula, the Eastern Han Dynasty only controlled the north in the later period, and several counties in the south were occupied by local ethnic groups.However, during the Jian'an period (196-219 A.D.), the Gongsun regime, a local separatist force, resumed its rule over the south and established a new Daifang County.The Gongsun family and the subsequent Wei and Western Jin basically controlled the area east of the Beidafeng Mountains in northern North Korea. After Goguryeo moved its capital to Wandu City (in today's Ji'an City, Jilin Province) in 209, it became stronger and stronger, gradually expanding southward, and finally completely occupied Lelang County at the end of the Western Jin Dynasty (313 AD).At about the same time, Daifang County was annexed by Mahan in the south.The more than 400-year history of the Central Plains Dynasty setting up formal administrative institutions on the Korean Peninsula ended.Goguryeo continued to invade the westwards of Liaodong and Xuantu, which belonged to the former Yan and the later Yan successively. After many battles, they obtained the land east of the Liaohe River in 404. In 427, Goguryeo moved its capital to Pyongyang, North Korea, which marked that Goguryeo had become an independent country outside of China.

During the period of the Sixteen Kingdoms, Tuyuhun, which lived in the Huangshui River Basin and the upper reaches of the Yellow River, rose and expanded southward to the present-day Songpan County of Sichuan.Later Tuyuhun was frustrated and withdrew, and the Qiang people entered present-day southern Gansu and northern Sichuan.In the Northern Zhou Dynasty, the Qiang people here were expelled and Dangchang County was established.This is also the first time that the Central Plains regime has established a formal administrative region in the local area. After the Eastern Jin Dynasty, the four regimes of Song, Qi, Liang, and Chen were successively established in the south.The capitals of these regimes were all located in Jiankang (now Nanjing City, Jiangsu Province, the original Jianye, which was changed to avoid the taboo of Emperor Min of Jin Dynasty), and only in the reign of Emperor Liang Yuan (552-555 AD) did they move their capitals to Jiangling in less than three years. .Contrary to the local expansion of the Central Plains regime in the north, the territory of the Han regime in the south is always shrinking.

Although the areas inhabited by ethnic minorities in the Southwest had established counties and counties during the reign of Emperor Wu of the Han Dynasty, the administrative control of the central government was often limited to the areas around the political districts and along the lines of communication.During the Three Kingdoms period, Zhuge Liang of the Shu Kingdom vigorously developed and expanded the actual control area, but by the Western Jin Dynasty, some administrative areas had existed in name only.Since the Eastern Jin and Southern Dynasties were always busy defending the north and dealing with internal power struggles, they did not take care of the management and development of the southwest border region; coupled with improper governance by local officials, and even cruel oppression of local ethnic groups, rebellions of varying scales occurred from time to time.However, until the middle of the Southern Dynasties, Ningzhou, located in today's Yunnan and western Guizhou, existed in name and officials were sent by the imperial court.In the second year of Taiqing (548 A.D.), the Hou Jing Rebellion broke out, and the governor of Ningzhou was ordered to rescue the capital and left the government.The local Cuan [cuan] barbarian wealthy family took the opportunity to break away from the Liang Dynasty in 550.Under the influence of Cuanman in Ningzhou, the surrounding tribes became self-reliant one after another. Therefore, there are no counties and counties of the Southern Dynasties in the south of the Yangtze River and Dadu River in Sichuan, western Hunan, and western Guangxi.

The southernmost part of the territory of the Han Dynasty is Xianglin County in Rinan County.In 192 A.D. (some say in 137 A.D.), the local Qu Kui established Linyi State and broke away from the Han Dynasty. As a result, the southern border of the Han Dynasty retreated from 13° north latitude to 16° north latitude.During the Three Kingdoms period (220-265 A.D.), Linyi expanded to the north again, annexed Xijuan County, and advanced to 17° north latitude.Around the end of the Southern Dynasties, Linyi occupied the remaining three counties of the original Rinan County, and the southern border of the Southern Dynasties retreated to the 18° north latitude line.