Western European feudal society was traditionally divided into three "estates" (social classes). The first estate was the church. The second estate was the nobility, including knights. It was common for aristocrats to enter the clergy, thus shifting from the second to the first estate. The third estate consisted of the commoners. Women were classified differently. They also had estates, which are categorized as virgin, wife or widow.

In the Holy Roman Empire, the clergy was represented by the independent prince-bishops, prince-archbishops, and abbots of the many monasteries. The nobility consisted of independent aristocratic rulers: secular electors, kings, dukes, margraves, counts and others. Burghers consisted of representatives of the independent imperial cities.