In ancient times, two clans in our countryside often fought for tens or hundreds of years in order to compete for water for irrigating farmland, and the whole village was old and young.
People of the two clans lived in mixed quarters, but the two surnames quarreled for hundreds of thousands of years without intermarriage, and they did not interact with each other. In modern terms, the two clans have remained at war for hundreds of years, and have not signed peace treaties for generations or even generations of each other. So neither clan ended up becoming one.
The so-called foreign wars have not moved for a hundred years, such as the Hundred Years' War between Britain and France. Essentially, it is a fight between two villages, and this fight may last for several lifetimes, but it will never fight them into the same country.
Ancient Europe was the real "feudal system", and the largest in Europe at that time was nominally the Roman Catholic Pope, but he was different from the Chinese emperor, and his power was much smaller. He had many economic, cultural, and spiritual privileges, but had little secular authority.
Secular rule was mainly vested in the king, who used the "system of mining" to divide the land among those who had done the credits below, on the condition of serving cavalry for life. The feudal lords who owned Caiyi enjoyed full administrative, judicial, military and financial powers over their lands.
Therefore, the kings of ancient Europe wanted to fight, not mainly to listen to the pope, but to win over the dukes, marquises, counts, viscounts, barons, knights, which really had land, power, and money, because they needed to pay for people.
This is the same as before the Qin Dynasty unified the world, the monarchs of our princely states needed to fight. The forms may be different, but the essence is not much different.
The monarch must first gather the various patriarchs together for a drink and eat a roasted whole lamb, and discuss at the wine table which tribes will bring how many soldiers and horses to go out on the battlefield, and how to distribute the spoils after the battle? All were discussed, and the tribes themselves sent out weapons, grain and grass, and came to obey the unified orders of the monarch.
And why do we "the world will be divided for a long time, and the world will be united for a long time", and the dream that everyone strives for will always be a unified central dynasty?
This is because more than 2,000 years ago, we entered a unified centralized dynastic society. This pioneer was Qin Shi Huang, and the county system inserted the central government's ruling power into every ordinary household.
So we completely bid farewell to the real "feudal society" more than 2,000 years ago. The Great Unification Dynasty will collapse because of the cyclical law, but then a new dynasty will be replaced.
That's why foreign wars have been fought non-stop for hundreds of years, and in the end they are still two countries. And we will never exceed two or three hundred years, and we will form a unified central dynasty.