Question

Why were serfs tied to the land?

Answer 1

Serfs paid the owner of the land (in the form of labor) to be able to live on the land and have protection, if the serf were to leave. It was usually an unspoken agreement that they serf would stay on the land. If you still need further information you might find some on http://www.thefinertimes.com/Middle-Ages/serfs-in-the-middle-ages.html