Feudalism, contractual system of political and military relationships existing among members of the nobility in Western Europe during the High Middle Ages. (It had nothing to do with blood feuds; the two words came to be spelled alike in the 17th century, but have no etymological relationship.) Feudalism was characterized by the granting of fiefs, chiefly in the form of land and labor, in return for political and military servicesa contract sealed by oaths of homage and fealty (fidelity). The grantor was lord of the grantee, his vassal, but both were free men and social peers, and feudalism must not be confused with seignorialism, the system of relations between the lords and their peasants in the same period. Feudalism joined political and military service with landholding to preserve medieval Europe from disintegrating into myriad independent seigneuries after the fall of the Carolingian Empire.When the German invaders conquered the western Roman Empire in the 5th century, they destroyed the professional Roman army and substituted their own armies, made up of warriors who served their chieftains for honor and booty.
The warriors fought on foot and lived off the countryside. As long as they fought one another, they needed no cavalry. But when the Muslims, the Vikings, and the Magyars invaded Europe in the 8th, 9th, and 10th centuries, the Germans found themselves unable to deal with these rapid-moving armies. First, Charles Martel in Gaul, then King Alfred in England, and finally Henry the Fowler of Germany provided horses for some of their soldiers to repel the raids into their lands. It is not certain that these troops fought on horseback, but they could pursue their enemies faster mounted than on foot, and as stirrups were then coming into use, it is probable that cavalry actions began to take place in this same period.
They were certainly occurring in the 11th century.