1. serf~ a laborer (slave) under the feudal system to work on his/her lord's estate, many of them were considering nothing to the nobles.
2. Knight~ A knight is a person granted an honorary title of knighthood by a monarch or other political leader for service to the monarch or country, especially in a military actions.
3. Noble~ A noble is usually an individual that was either born into the class of noble, or worked extremely hard to get the status. Nobles usually were politicians, aristocrats, and served the monarchs in court.
4. King~ A monarch (king) may exercise the highest authority and power in the state, or others may wield that power on behalf of the monarch. Typically a monarch either personally inherits the lawful right to exercise the state's sovereign rights (often referred to as the throne or the crown) or is selected by an established process from a family or cohort eligible to provide the nation's monarch.
5. Vassal~ A holder of land by feudal tenure on conditions of homage and allegiance. A vassal is also at the status of a serf at times, but usually are more the slave type than a serf.
Hope this helps.
