In the Middle Ages, society was classified into groups. There were the clergy, such as bishops and monks, the nobility, i.e. kings and knights, and the commoners, i.e. the more simple people such as peasants and artisans. Children automatically became part of the group to which their parents belonged. So that people could see at once which group someone belonged to, there was sumptuary law.

The rules of sumptuary law determined which materials, colours and clothing people were allowed to wear. The nobility were allowed to wear fine materials such as silk or velvet, and they were the only group allowed to wear the colour blue. Peasants had simple clothing made of wool or linen, in colours that were mostly dark. Clerics too wore special vestments which enabled them to be recognised at first glance. Anyone not adhering to these rules could be punished.