Machiavelli's viewpoint in The Prince: Why did French King Louis XII of France annex the weak country? ...

It is explained clearly in this post. I extracted a part. If you want to know more clearly, just read the post bar directly ~ ~ ~

King Louis XII of France of France quickly occupied Milan, but soon lost Milan. All he needed was Rodovico's own army to drive out Louis XII of France of France. This is because the people who first opened their doors to the French king realized that their wishes and the benefits they expected would not come true, so they could not stand the new monarch.

Those places that once rebelled will not be so easy to fall after being conquered again, because the rulers will take advantage of the opportunity provided by rebellion to resolutely punish criminals, find out suspicious elements and consolidate their position against weak links. So France lost occupied Milan for the first time, as long as a Duke of Lodovico rose up at the border, but if France wants to lose Milan again, it needs the whole world to resist him, defeat his army and expel him from Italy for the above reasons. However, the French lost to Milan for the second time. The reason for the first loss has been discussed before. Now let's talk about the reasons for the second defeat, consider what the French king did at that time, and put yourself in his shoes to think about whether there is a better way to rule the territory he conquered than the French king. In my opinion, those countries that have been annexed by conquerors to their ancient countries, or countries that belong to the same region and use the same language as the conqueror countries, or not, must be one of them. If they are in the same area and the people in those countries are not used to living freely, then it is easiest to rule these countries. As long as all the monarchs are cut off, these countries can be firmly ruled. Because as long as they keep their previous state in other things and don't change their customs, people will continue to live safely, as people have seen in Brittany, Burgoni, Gascony and Normandy, which already belong to France. Although there are some differences in language, the habits are the same, so it is easy to blend in. In order to rule these conquered areas, we must pay attention to: on the one hand, we must eliminate the bloodline of their old monarch, on the other hand, we will not change the previous laws or taxes. In this way, in a very short time, they will be integrated with the ancient kingdom. However, if the conquered country and the conquered country are different in language, habits and various systems, there will be many difficulties. In order to rule the conquered country, besides great luck, great efforts are needed. It may be one of the most effective and powerful ways for conquerors to go there and stay there in person. Because it will make his career more stable and lasting. For example, this is how the Turks ruled Greece. If the King of Turkey had not stayed in Greece, even if he took other measures to rule Greece, he could not rule that country. Because if the monarch is in the local area, he can detect all the signs of riots and quickly eliminate them. Otherwise, he will only know when the chaos occurs, and it will be too late for him to clean up the chaos. In addition, the subjects were satisfied that the monarch could meet their demands in time, so that the place would not be plundered by his officials at will. In this way, those who are willing to be good citizens will definitely support the monarch more, while those who have two hearts will definitely be more afraid of him. As for those who try to attack from the outside, they must be extremely cautious, because as long as the monarch is stationed here, it is difficult to seize land from him. A better way is to emigrate to one or two key places in that country, which is very necessary, because otherwise you will send a large number of infantry and cavalry there, and any one of them will be one of them. Immigrants don't need to spend a lot of money, just pay a small fee. In doing so, the monarch only offended some people who provided land and houses to new immigrants, and these people only accounted for a very small number of that country. At the same time, the infringed people are scattered all over the country, very poor, and can not pose a threat to the monarch; As for those who have not been hurt, it is of course very easy to appease them, but also because they have to be careful not to do anything wrong in order to avoid the same experience as the plundered people.