In the social structure of the Middle Ages, serfs occupied the lowest position. They were peasants bound to the land on which they resided and obligated to perform labor obligations for landowners in exchange for permission to reside and cultivate a small holding. They were not slaves but they had limited personal freedom and could not leave the land or alter their social situation without gaining explicit approval from their landlord or lord.
Serfs formed crucial part of a feudal society as they constituted a a substantial portion of society, and their labor helped sustain those social class above them such as knights, landlords, nobility, and others who engaged in military , religious economic, or administrative service and activities