Feudalism began between the 8th and 9th centuries. It was first recognized in France, and later spread to most countries of western Europe. When Charlemagne died there was no strong ruler to take his place. That was when feudalism was established as the main system of government and way of life in Medieval Europe. Europe was politically divided. It was hit by several invasions of the Vikings, the Magyars, Muslim pirates, and others. People could no longer look to a central ruler for protection. They had to seek the protection of the lords, who had armies of their own. To expand ones power and wealth, lords would make alliances with other nobles. A lord would grant land to another noble in exchange for protection and military services. This grant was called a fief. Those who received the fiefs were called vassals. Within the fief, the vassal was the highest authority. Fiefs could be various sizes. Some were single estates just big enough for a knight and his family. Others were large. As big as an entire country or province.

The vassals promised the lord military services. Military service was their main obligation. This service was usually limited to 40 days a year. Vassals also owed payments called aids on certain occasions. When a lord's oldest daughter married, the vassal made special payments as a gift. The vassal also had to pay for the arming of the lord's oldest son when he became a knight. Vassals pledged to pay the ransom for their lord in the event of his capture during war.

A vassal's son usually inherited his father's responsibility to serve and pay aids. Before receiving the fief, the son had to pay a fee called a relief. The amount of payment all depended on the size of the fief.

The lord in turn, had obligations to his vassals. He promised the vassal protection and could not deny the vassal's claim to the fief. If at any time an outsider tried to steal the vassal's fief, the lord would join in with his other knights to aid him.