In feudal relationships, the “lord” was the individual or institution that had authority over a vassal, but the word lord was also used to describe the person or institution that had economic and political authority over peasants who lived in villages and farmed the land. Thus a vassal in one relationship was a slightly different type of lord in another. Most European people in the early Middle Ages were peasants who lived in family groups in villages or small towns and made their living predominantly by raising crops and animals. The village and the land surrounding it were called a manor. Some fiefs might include only one manor, while great lords or kings might have hundreds of manors under their direct control. Residents of manors worked for the lord in exchange for protection, a system that was later referred to as manorialism. Free peasants surrendered themselves and their lands to the lord’s jurisdiction. The land was given back, but the peasants became tied to it by various kinds of payments and services. Thus, like vassalage, manorialism involved an exchange. Because the economic power of the warring class rested on landed estates worked by peasants, feudalism and manorialism were linked, but they were not the same system.

Local custom determined precisely what services villagers would provide to their lord, but certain practices became common throughout Europe. The peasant was obliged to give the lord a percentage of the annual harvest. The peasant paid a fee to marry someone from outside the lord’s estate. To inherit property, the peasant paid a fine. Above all, the peasant became part of the lord’s permanent labor force. With vast stretches of uncultivated virgin land and a tiny labor population, manorial lords encouraged population growth and immigration. The most profitable form of capital was not land but laborers.

In entering into a relationship with a manorial lord, free farmers lost status. Their position became servile, and they became serfs. That is, they were bound to the land and could not leave it without the lord’s permission. Serfdom was not the same as slavery in that lords did not own the person of the serf, but serfs were subject to the jurisdiction of the lord’s court in any dispute over property and in any case of suspected criminal behavior.

The transition from freedom to serfdom was slow. In the late eighth century, there were still many free peasants. And within the legal category of serfdom there were many economic levels, ranging from the highly prosperous to the desperately poor. Nevertheless, a social and legal revolution was taking place. By the year 800, perhaps 60 percent of the population of western Europe — completely free a century before — had been reduced to serfdom. The ninth-century Viking assaults on Europe created extremely unstable conditions and individual insecurity, increasing the need for protection, accelerating the transition to serfdom, and leading to additional loss of personal freedom.

Though serfdom was not slavery, the Carolingian trade in actual slaves was extensive, generally involving persons captured in war or raids. Merchants in early medieval towns used slaves to pay the suppliers of the luxury goods their noble and clerical customers desired, most of which came into Europe from the East. The Muslim conquest of Spain produced thousands of prisoner-slaves, as did Charlemagne’s long wars and the Viking raids. When Frankish conquests declined in the tenth century, German and Viking merchants obtained people on the empire’s eastern border who spoke Slavic languages, the origin of our word slave. Slaves sold across the Mediterranean fetched three or four times the amounts brought within the Carolingian Empire, so most slaves were sold to Muslims. Christian moralists sometimes complained about the sale of Christians to non-Christians, but they did not object to slavery itself.