Why did some towns become free?
the lords didn't want the responsibility.
the merchants bought the land.
the lords sold the land because they needed money.
the village protested and won their freedom.

Towns became free for multiple reasons, but what would happen was that a lord would sell the lands because he needed the money and would flee other places or the merchants bought the lands, athough this was less frequent than the first.

They most like influence us and there self