In ancient times, due to the backwardness of the mode of production economy and the mode of political rule, people's ability is limited, but in order to be able to enjoy more resources, the possession of land is a recognized way to get rich, so most of the countries established in the feudal society in history have the desire to expand the territory, and there are many emperors who unified China in Chinese history.
However, the han people's experience in the development of feudal regime is sufficient, although the country is strong and can expand the land indefinitely, but at the same time, our ancestors will also think that the management of the region must also be in line with the ability, too small to develop, too big to touch, so China's land scope increases and decreases within a certain range.
Although feudal society is a centralized system, but the feudal state is "home to the world", its essence is impossible to let the land develop indefinitely, not to mention that feudal society can only support the general life expectancy of hundreds of years, let alone both expansion and defense of the country.
Han Wu TangZong, still can not maintain more than 400 years of inheritance, foreign invasion to obtain the regime is even more unable to, on the one hand, because foreign tribes generally conquer the Central Plains by force, and can not formulate a relatively perfect management system, so China often says that Hu Yu has no luck for a hundred years, although the Qing Dynasty is an exception, but the Qing Dynasty is already the last period of the feudal dynasty.
But the northern nomads did have the ability to expand their territory by force, just like the blitzkrieg invented by Germany during World War II, when the speed of war was fast enough, more and more places were occupied, and the rule and expansion of the Mongol Empire was like this, the Mongols not only fought extremely, but also had great ambitions for expansion, so that the Mongol Empire had nearly 24 million square kilometers of land in its heyday.
The power of the Mongol Empire originated in the Mongolian plateau, and the founder was genghis Khan, who was famous in ancient and modern China and abroad, and during genghis Khan's lifetime, Mongolia was thriving and the land was constantly enriched. Later, the Central Plains also tended to perish under the threat of powerful Mongol force, and the Southern Song Dynasty was finally broken in the hands of The Mongol Yuan after years of confrontation with the northern regime, but the ghosts under the sword in the hands of the Mongols were not only China.
Of course, Genghis Khan did not see the day when the Yuan Dynasty ruled China, after his death, the Mongol Empire was inherited by his heirs, and also went west many times and occupied China, but then the empire gradually fell apart after the death of his heir Möngke, which was the doomed fate of the feudal empire, after the death of the great emperor, it was his descendants and brothers who replaced him, just like the Roman Empire was also divided into three, slowly evolving into so many regimes in Europe, unable to move towards reunification.
Of course, the greatness of the Mongol Empire lies in the strength of their forces, the Mongols often go everywhere they go, and they slaughter the city, and it is precisely because of this cruel nature that the Mongols fought all the way to the Danube River in Europe, if it were not for Möngke's early death, his relatives would have returned to fight for territory, and perhaps the Mongols could rule the entire Eurasian continent.
The Mongol Empire included the Then Yuan Dynasty, the Chincha Khanate, the Chagatai Khanate, the Ilkhanate, and the Wokoutai Khanate, and of course there were some vague records, not to mention small countries and small cities. Today's northern desert, north China, northeast China, Tibet, western regions, Central Asia, West Asia, Eastern Europe and other regions have been subject to Mongol rule.
After the sudden death of Möngke Khan, in 1260 the Mongol Empire infighting, Kublai Khan and Ali did not fight for power, Although Kublai Khan finally won the victory, but the Mongol Empire also disintegrated, Kublai Khan's brothers and relatives successively acquired the land occupied by the original Mongol Empire, but the empire was divided, after all, this is also the inevitable move of the founding of the country to reward the meritorious, and no one can manage the huge land.
Of course, during the Yuan Dynasty, China's territory also covered a vast territory, totaling 13.72 million square kilometers, including present-day Kazakhstan, Tajikistan, Kyrgyzstan, Afghanistan, Bhutan, Mongolia, Russia, North Korea, North Korea, Myanmar, Thailand, North Korea, Laos, Nepal, Pakistan and other places.
The Yuan Dynasty really did not rule in China for more than 100 years, because the Yuan Dynasty really did not adapt to the local Chinese culture, and there were various conflicts with the local culture at the beginning, the Mongol Empire had ceased to be glorious from the day it was dissolved, and after the fall of the Mongol Empire, the Mongol regime never rose again.
[Reference: History of the Mongol Empire, etc.]