In the eighth year of Zhiyuan (A.D. 127 1), on March 28th, Kublai Khan of Yuan Shizu issued a decree to change the capital of Beijing into a metropolis, and Beijing became the capital of a unified dynasty for the first time. Historians of later generations hold different opinions on why Mongolian rulers made Beijing their capital, especially the general public. In fact, the changes in the capitals of political power in past dynasties reflect the changes in the whole society and even the times.
Since the late Tang Dynasty, the main frontier troubles of the Central Plains regime no longer came from the northwest, but from the Qidan tribe rising in the northeast. In addition, the economic center gradually moved from the lower reaches of the Yellow River to the south of the Yangtze River, and its capital, Guanzhong, could not guard the border, which also caused huge water transportation costs, so the rulers had to turn their attention to other places. At this time, Kaifeng, which borders Zhao Yan in the north and Jianghuai in the south, has a large population and convenient transportation, replacing the dilapidated Chang 'an and Luoyang and becoming the capital of Hou Liang, Houjin, Houhan, Houzhou and Northern Song Dynasty. The rise of Kaifeng city is entirely due to the convenience of land and water transportation, so its rise and fall is closely related to the smooth flow of the canal.
If convenient transportation is Kaifeng's greatest advantage, flat terrain and no danger are Kaifeng's most fatal defects. In addition to strengthening the city defense and stationing troops in the suburbs of Beijing, Song Ting had no choice, which led to a large amount of military expenditure, which was closely related to the policy of "guarding the outside from the inside" brought by Kaifeng, the capital. Most of the other regimes are based on local governments. For example, the Han Cheng regime has profits, so Chengdu is the capital; Qianliang occupied Liangzhou, so Guzang (now Wuwei, Gansu) was the capital.
On the other hand, Beijing has not yet become the capital of a country. After the post-Jin regime was ceded to Liao Dynasty, Youzhou was just an ordinary state. It was not until the first year of Huitong (938) that Yelvdeguang, Emperor Taizong of Liao Dynasty, promoted it to the Western Jin Dynasty, which was called "Nanjing" in history, and because it was the capital of Yan State in ancient times, it was called "Yanjing" as the capital of Shangxing Huanglinfu (now Zuo Qi, Bahrain, Inner Mongolia). It is worth mentioning that there were four capitals in the Liao Dynasty, namely, Dading House in Zhongjing, Xijing House in Xijing and Liaoyang House in Tokyo, and the status of "Nanjing" was not prominent.
In the 23rd year of Shaoxing in the Southern Song Dynasty (A.D. 1 153), Wan Yanliang, the king of Hailing, moved the capital from Huining House in Shangjing (now Harbin, Heilongjiang) to Daxing House in Zhongdu (now Beijing), and Beijing with thousands of years of history turned over for the first time. In jurchen's view, Yan Dou is bordered by mountains in the north, the Central Plains in the south and the Bohai Sea in the east, with a unique geographical environment, far exceeding Kaifeng, Luoyang, Xi 'an and Nanjing. If you look at the map carefully, you will find that Beijing lies between the North China Plain, the Mongolian Plateau and the Songliao Plain, with Yanshan Mountain in the northwest and Taihang Mountain in the southwest. Liaodong Peninsula and Shandong Peninsula guard the Bohai Sea near Beijing. Such a unique terrain is bound to arouse the interest and attention of the rulers.
But for Mongols, it doesn't matter where the capital is, as long as the nomadic tradition can be maintained-at least Genghis Khan himself has no intention of taking Beijing as the capital. However, during the period of Yuan Shizu, the situation changed significantly. After careful investigation, Liu and Guo Shoujing, the Han mentoring trusted by Kublai Khan, unanimously decided that Beijing was the most ideal capital city, but the only fly in the ointment was the lack of water. So the two men drew water from Yuquan Mountain and entered Beijing through two water veins on the ground and underground. Among them, the above-ground water source flows into Tonghui River through Taiping Bridge. Because water comes from the west and symbolizes "gold" in gossip, it is named "Jinshui River". The underground water vein later became a sacred place for the imperial palace to worship the "Longquan Well God".
Some Mongolian aristocrats also realized the geographical advantage of Beijing in the battle-being at the intersection of east and west terrain, not only being close to Mongolian homeland and nomadic tribes in northeast China, but also being able to suppress the south by squatting down, controlling all counties in the country in advance and moving back to Mobei to regroup. So they proposed to build a metropolis on the basis of Liao and Jin. The reason for the construction was that Beijing was burned to the ground when Genghis Khan led the army to destroy the gold. According to the Yuan Dynasty's Biography of Batunan, Batunan once remonstrated: "The land of secluded swallows is surrounded by dragons and tigers, and the situation is magnificent, with Jianghuai in the south and Shuomo in the north. And the son of heaven must be in the middle to accept worship from all directions. If Wang wants to rule the world, he must leave Yan. "
After careful consideration, Kublai Khan accepted this proposal and changed Yanjing into a metropolis on March 28th in the eighth year of Zhiyuan (A.D. 127 1), and appointed Liu to be in charge of the design and construction of the metropolis. Therefore, referring to the traditional geomantic theory of the Han nationality, Liu laid out the layout according to the pattern of "former dynasty and later dynasty, left ancestors and right societies", which took 24 years to build, which also laid the outline of Beijing today. In addition, when the northern nationalities establish a unified dynasty or the main threat comes from the northeast, the capital Beijing is of great significance to maintaining their ancestral home and national movement. Therefore, since the capital was established in the Yuan Dynasty, Beijing has ushered in a real take-off and become the capital with the longest duration in the late feudal society of China.