Feudalism is an economic and political system developed in the Middle Ages of Europe and the Bubonic Plague was one of the reasons feudalism fell.
More money and rights!
The Bubonic Plague impacted Europe's population of 24 million people dead and very little of the civilization survived.
We have to or else they are going against us and we need workers!
After the plague, the power of the nobles decreased and shifted to the common people.
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The common people demanded more rights and money which lead the weakening of the feudal lords and the manor system.
This contributes to the Bubonic Plague because so much of the population was gone therefore, the feudal lords were forced into giving them rights and money or else the common people would go into resentment.
Common people obtained their power constantly asking for money in order to stay. They obtained it by revolting against the lords when they tried to bring thing the way it used to be. It changed the commons people lives a lot because they have power they didn't have before and money which makes them somewhat powerful.