Final answer:
Cannons and bombards were the primary weapons used to tear down castle walls, marking a significant shift in medieval military technology and tactics.
Step-by-step explanation:
The name of the weapons used to tear down castle walls were cannons and bombards. These heavy artillery pieces used gunpowder to launch projectiles capable of breaching the stone fortifications that had traditionally protected castles and city walls. The adoption of cannons significantly changed military tactics and led to the development of new forms of fortresses with earth banks and star-shaped designs to resist such attacks. This transition in military technology marked a shift away from the prolonged sieges of old, where attackers had to starve out a city or castle, to more aggressive strategies that could quickly compromise a fortress's defenses.