Serfs were the peasants who lived on either a manor or a fief, the two organizing entities of the Middle Ages (500–1350). They performed labor and were bound to the lord of the property where they lived and worked. A serf was somewhere between a free person and a slave: Though the word serf is derived from the Latin word servus, meaning “slave,” the serfs had certain rights, which were governed not by law but by custom. One such custom was that a serf who could escape his lord for one year and a day was then considered free. A free peasant was called a villein, a village commoner.