How was a town able to become independent of a feudal lord ?

When merchants became richer due to increased trade fostered by town life, they started to negotiate with their lords for the payment of a fixed amount (as opposed to a cut of their profits) to be paid annualy to the lord, thus gaining independence to govern themselves.

besides the fact that abraham lincoln abolished slavery, and greatly benefit black people, he had a heavy impact of the definition of what democracy was, and should be.