Why couldn't serfs move to the city?

Serfs could not move to the city primarily due to the legal and economic constraints imposed by the feudal system. They were bound to the land owned by a lord, who had control over their lives and movements. Leaving the manor without permission was considered a violation of their obligations, and they faced severe penalties if caught. Additionally, cities often had their own regulations and social structures that made it difficult for serfs to integrate and establish a new life.