Towers of medieval castles were usually made of stone, wood or a combination of both (with a stone base supporting a wooden loft). Often toward the later part of the era they included battlements and arrow loops. Arrow loops were vertical slits in the wall through which archers inside shot arrows at the attackers, but made it extremely difficult for attackers to get many arrows back through at the defenders.
Towers of medieval castles were usually made of stone, wood or a combination of both (with a stone base supporting a wooden loft) Often toward the later part of the era they included battlements and arrow loops. Arrow loops were vertical slits in the wall through which archers inside shot arrows at the attackers, but made it extremely difficult for attackers to get many arrows back through at the defenders.