Feudalism was a system of organizing society that dominated much of medieval Europe for several hundred years, especially from around 900 to 1400 AD. In this system, powerful lords controlled vast amounts of land and granted portions of it to less powerful nobles, knights, and vassals in exchange for military service and loyalty. Think of it like a pyramid: the king sat at the top, great lords below him, lesser nobles below them, and peasants at the bottom, working the land.

Here's how it worked: a lord might give a knight a large estate in return for the knight's promise to fight for him when called upon. That knight became the lord's vassal, someone who owed loyalty and service. The knight, in turn, might have peasants called serfs working his land. These serfs weren't slaves, but they couldn't leave the land freely and had to give much of their harvest to the knight.

Everyone had a role and obligations in feudalism. Lords provided protection and land. Vassals provided military service. Serfs provided labor and food. When the system worked well, it created stability in a dangerous time when invasions and warfare were common. When it worked poorly, it trapped people in rigid social classes with little chance to improve their lives.

Feudalism gradually changed and weakened as trade increased, cities grew larger, and strong national governments emerged. Today we use feudal to describe anything rigidly hierarchical and old-fashioned, like calling a strict school system “feudal” when students have no voice in decisions.