How did a peasent become free?

Answer 1

This is a complicated question, but the simple answer is that a combination of things worked to free the serfs. Most important was the fact that the Black Death made them valuable, and nobles tried to tempt them off each others land. Also there were kings who did not like the system. Lords had obligations to protect serfs and provide them with land, and as the population increased simultaneously with agricultural efficiency, it became desirable not to have those obligations but to charge rent. There were other factors.