There was little to no social mobility on medieval manors and people were born into their classes. Manors were the lords estate. Manors covered up to several miles and consisted of the lord's house, a church, workshops, and fields. Serfs were bound to their manors. The serfs rarely traveled 25 miles from their manors in their entire lives. Manors were the central piece of manorialism. Manorialism was the economic system used during the Middle Ages. The manors were self sufficient. Everything the people living on the manors needed was produced on the manor itself. The serfs farmed for the lords, vassals, and knights, while the lords and vassals provided the serfs with shelter, agricultural supplies and lands to farm. The knights provided the serfs with protection as they protected the manors. Since there was little need for coin money, the people who lived on manors mainly used a system of bartering.