In addition, in the "History of Yuan Angchao's Erroneous Column Biography" and "History of South Vietnam", there are also records of "Southern Humidity" and "Southern Humidity", indicating that during the Western Han Dynasty, China's Jiangnan region was not conducive to the development of agricultural economy, the climate was very warm and humid, and it was still a "hot and humid" land.
Topographic map of China
Spring and Autumn period to the end of the Western Han Dynasty, is a warm period in the history of our country, this warm period lasted for nearly 700 years, the average annual temperature of the Qin and Han Dynasties is about 1 to 1.5 ° C higher than we are now, at that time, the Yellow River Basin has plum trees growing, the Guanzhong Plain has a large number of bamboo forests, and even lychee trees can survive in the Guanzhong area, the Yellow River Basin is warm and humid, then, naturally, the Jiangnan region and the Lingnan region are relatively speaking, it is a "humid" place.
However, around the 1st century BC, that is, the beginning of the Eastern Han Dynasty at the end of the Western Han Dynasty, the global climate began to turn cold, and this cold period lasted until the early years of the Tang Dynasty, and reached its peak during the Sixteen Kingdoms period of the Eastern Jin Dynasty, that is to say, the climate of the entire Eastern Han Three Kingdoms Wei and Jin Southern and Northern Dynasties period was cold, and the average annual temperature at that time was about 1 to 2 ° C lower than now. Wrap the branches tightly with pujab, otherwise, the pomegranate tree will freeze to death in winter, and now in Shandong, Henan and other places in China, the pomegranate tree can survive the winter in the wild.
earth
After the climate of the Yellow River Basin turned cold, naturally, the "humble" environment in the Jiangnan region that was not conducive to the development of the agricultural economy gradually disappeared, so as early as the Eastern Han Dynasty, the Han people in the Central Plains set off a wave of migration to the Jiangnan region, and Wu County (now Suzhou City, Jiangsu Province), Huiji (present-day Shaoxing City, Zhejiang Province), Yuzhang (present-day Nanchang City, Jiangxi Province) and other places saw a growing number of hukou and an increasingly expanding cultivated land area.
At the same time as the large-scale migration of han people in the Central Plains to the Jiangnan region, the northern ethnic minorities also began to migrate to the interior on a large scale from outside the Country, the global climate turned cold, and the impact on the northern grasslands was also more obvious, in the autumn and winter, the time of the grass and trees withered and yellowed was advanced, and the frost and snow weather increased, which was very unfavorable for the development of animal husbandry, and the nomadic people had always had the habit of living by water and grass, so there was a climax of the inward migration of ethnic minorities, and the rulers of the Eastern Han Dynasty in order to supplement the shortage of labor in the interior and strengthen the military strength of the north. Ethnic minorities are often encouraged to move inland, and the Book of Jin records: "The people in Guanzhong, more than a million mouths, the rate is less, and the Rong Di lives in half." ”
Commoners during the Wei and Jin dynasties
During the Three Kingdoms period of the Eastern Han Dynasty, a wave of migration from ethnic minorities to the Yellow River Basin and the Han nationality in the Central Plains to the Yangtze River Basin was formed, and this wave of migration reached its peak from the end of the Western Jin Dynasty to the Sixteen Kingdoms period of the Eastern Jin Dynasty.
After the Western Jin Dynasty destroyed Wu, it became another great unified dynasty since the Han Dynasty, but as a great unified dynasty, the Western Jin Dynasty did not have a long-lasting reign and prosperity, and the "rule of Taikang" during the reign of Emperor Wu of Jin only lasted for ten years, and after the death of Emperor Wu of Jin, the Western Jin Dynasty soon fell into the "Rebellion of the Eight Kings" for 16 years.
The "Rebellion of the Eight Kings" at the end of the Western Jin Dynasty brought a deep disaster to the Western Jin Dynasty, the Western Jin Court lost control of the northern counties, and the Xiongnu Liu Yuan and shi Le of the Qiang people successively rebelled against the Jin, opening the prelude to the "Five Hu Chaos".
At the same time, in Shaanxi, Sichuan, Henan, Hunan, Hubei and other places, there were also displaced people uprisings, such as: Li Te, Li Xiong uprising, Zhang Chang uprising, Wang Ru uprising, etc., Qin Yong six counties displaced people forced into Shu, indirectly led to the later Li Te, Li Xiong uprising, in 304, Li Xiong established a political power in Chengdu, known as "Cheng han", unveiled the prelude to the history of the Sixteen Kingdoms.
In April of the fifth year of the Western Jin Dynasty (311 AD), Shi Le defeated the 100,000 troops led by Wang Yan of the Western Jin Dynasty at Ku County (present-day Luyi County, Henan Province), and since then, the main force of the Western Jin court has been basically wiped out, and in June of that year, Liu Yuan's adopted son Liu Yao (劉曜) attacked Luoyang, and more than 30,000 ministers of the Western Jin Dynasty were killed, known in history as the "Disaster of Yongjia", in the fourth year of Jianxing (316 AD), Liu Yao attacked Chang'an, Emperor Huan of Jin became a prisoner, and the Western Jin Dynasty officially perished in this year.
After the Yongjia Rebellion, the Central Plains fell into a state of war, the Central Plains Han people moved south one after another, known in history as "Yongjia Nandu", when Liu Yao attacked Luoyang, "Zhongzhou shi women avoided chaos in the left of the river sixteen seven", when Liu Cang attacked Chang'an, "more than 4,000 families left in Hanzhong".
Nobles and their attendants during the Wei and Jin dynasties
In 317, the news of the capture of Emperor Huan of Jin reached Jianye (present-day Nanjing, Jiangsu Province), where Sima Rui re-established the Jin Dynasty in Jiangnan, known in history as the "Eastern Jin Dynasty", and the following year, Sima Rui was proclaimed emperor for emperor of Jin yuan. When Sima Rui rebuilt the Jin Dynasty in Jiangnan, a great locust plague broke out in Jizhou, Qingzhou, Yongzhou, Sizhou and other places in the north, and in 318 AD, a locust plague broke out in Qingzhou, Xuzhou, and Jizhou, and the locust plague for many years caused the people of the northern states and counties to move south continuously.
The migration activities of northern immigrants to the Yangtze River Basin continued until the Liu Song Dynasty, so how many people in the northern region of China migrated to the Yangtze River Basin from the Yongjia period of the Western Jin Dynasty to the great ming dynasty of the Song Dynasty And Emperor Xiaowu of the Southern Dynasty? Since there was no accurate demographic data at that time, we can only make a rough estimate based on the number of hukou in Qiao Prefecture, County, and County, after the northern population migrated to the south, the Eastern Jin Dynasty and the Southern Dynasty (Song, Qi, Liang, Chen) successively set up Qiao Prefectures, Counties, and Counties in the South to resettle the Shishu residents who migrated to the south, and the place names of these Qiao Prefectures, Counties, and Counties were generally the same as the place names of the original prefectures, counties, and counties, and by the Liu Song Dynasty, the population of Qiao Prefectures, Counties, and Counties was about 900,000, but this was only the number of people registered by the government, in fact, There are still many people who have not been registered, and some scholars believe that by the time of Emperor Xiaowu of the Song Dynasty, the number of northern immigrants and their descendants should be around 2 million.
During the Western Han Dynasty, China's population peak was 60 million, after the war from the end of the Eastern Han Dynasty to the Three Kingdoms period, the population of the Western Jin Dynasty was about 35 million, and the proportion of the population in the north at that time was about 55.5%, that is to say, during the Western Jin Dynasty, the population of the northern region was about 19.44 million, if after the Yongjia Rebellion, 2 million people migrated to the south, then at that time, at least more than 10% of the northern population migrated to the south, except for the Eight Kings Rebellion, the Yongjia Rebellion, the population lost, The proportion of actual immigrants is even greater.
Yongjia Nandu is not only the southward migration of the population, but also the southward migration of the Central Plains regime and the Chinese civilization, among the southward migration of the population, the Yiguanshi clan in the north accounts for a large part, and after the Eastern Jin Dynasty is partial to the south of the Anjiang River, the formation of the Langya Wang clan, the Chen Junxi clan, the Chen Junyuan clan, the Lanling Xiao clan and other clans are from the north.
Yongjia Nandu for the Han nationality, can be described as the whole country to move south, if there is no this migration, whether the Chinese civilization can continue, perhaps it is still a question, Sima Rui in the Jiangnan region to rebuild the Jin Dynasty, the Han people in the Central Plains regard the Eastern Jin Dynasty as orthodox, have gone south, because a large number of Central Plains Han people can establish overseas Chinese in the southern region, counties, counties, so that the Han population can always maintain an absolute dominant position, if there is no such absolute advantage, in the process of ethnic minorities inward migration, the Han nationality is likely to be assimilated, then, In the later historical period, whether there is a title of "Han nationality" may also be a question, Yongjia Nandu, can be said to be a great migration activity in the history of the Han nationality, the Eastern Jin Dynasty, the Southern Dynasty established the state of Jiangnan, at least culturally, for the Sixteen Kingdoms, the Northern Dynasty regimes, played a leading role, is conducive to the Sinicization of ethnic minorities in the north, if the Eastern Jin Dynasty can not gain a foothold in Jiangnan, but collapses for thousands of miles, then this leading role in culture will no longer exist, the Sinicization of the Northern Wei may be delayed. Sima Rui's reconstruction of the Jin Dynasty in the Jiangnan region, although partial, played a very important role in preserving the culture of the Central Plains.