Why did medieval castles have towers that projected from the curtain wall?

Medieval castles featured towers that projected from the curtain wall primarily to enhance defensive capabilities against attackers.

By protruding from the main wall, these towers allowed defenders to direct flanking fire along the face and base of the wall, effectively denying attackers an undisturbed approach. This design was crucial for preventing enemies from using tactics like battering rams or mining, which required close, unprotected access to the wall's footing. Additionally, these towers were typically built higher than the curtain wall itself, providing archers and crossbowmen with a greater range to engage the enemy.1

Beyond their tactical utility, towers were often constructed with massive, protruding feet to further frustrate attempts at undermining the structure.1