"For much of history, in many places, the freedom of many people to move or to change their abode for reasons such as looking for work was severely restricted. In much of Western Europe during the Middle Ages and most of Eastern Europe from the 16th century onward, peasant farmers were serfs, tied to a particular location and unable to move without the permission of their lord. In China under most of the dynasties, people needed a pass to leave their county or province, which had to be produced on demand.
This kind of control on movement was not simply a feature of the Medieval period that faded away as time passed. In fact, there was probably more freedom of movement within kingdoms in that period than subsequently. The 16th and 17th centuries saw a major tightening of controls across Europe. This reflected and was driven by a growing panic over the problem of vagabondage, with poor and marginal peasants and agricultural laborers leaving their homes and wandering from one place to another looking for work. The outcome was a spate of legislation in most states that sought to stop this and to control both mobility and access to both paid work and poor relief."