Later in the Middle Ages, important people wanted more privacy and larger homes. It was easier to build new homes instead of trying to make the castles bigger, so some people moved out of castles into new homes. The use of gunpowder weapons also changed warfare and made castles less effective. Guns were introduced in the 14th century, and by the 15th and 16th centuries they were powerful enough to break castle walls. New types of fortification were invested, with shorter thicker walls, and using earth to absorb hits from cannonballs.