Europe became a feudal society because of a combination of political, economic, and social factors.
One of the main reasons was the collapse of the Western Roman Empire in the 5th century, which led to a lack of strong central government and a fragmentation of political power. This created a vacuum that was filled by local lords and landowners, who were able to establish their own power and control over their lands.
Another factor was the invasions of barbarian tribes, such as the Vikings, Magyars, and Moors, which created a need for local protection and led to the emergence of a warrior class.
Additionally, the system of feudalism provided a way for lords to organize and control the labor of the peasantry to produce food and other goods, which was essential for the economy.
Feudalism was a way to maintain order and stability under difficult circumstances.