Medieval castles became popular across Europe from the 10th century onwards. From this period until the end of the medieval era, castles evolved significantly and so did their overall structures and defenses.
The most vital military problem faced by a medieval castle was the possibility of facing a siege. If a siege was laid on the castle, it had to be appropriately equipped and defended in order to ward off the attacking force. In doing so a number of weapons were used by the defenders of the castle.
The Catapult was a weapon that was popularly used to attack a castle but it was equally effective in defending a castle. When defending a castle against an attack from the outside, the catapult was typically positioned in an open square or on top of a sizable tower.
It was then used to fire directly at enemy lines. The catapult was frequently aimed at destroying the siege towers and other siege engines of the attacking force.
However, a catapult could offer limited damage to the enemy forces because of its limited range and the fact that it was a cumbersome weapon to be used by castle defenders. On the other hand, when used to attack castle walls from the outside, a catapult was highly effective.
A more rudimentary type of weapon was simply rocks or stones. In desperate situations especially when a castle didn’t have a large enough garrison but enough household members, people inside the castle would simply pick up huge rocks and stones and start launching them from the castle walls.
If the attacking force had reached the castle walls, such a hail of rocks and stones from castle walls was a dangerous enough weapon to be taken seriously. Typically, rocks thrown from castle walls proved an effective defence against enemy soldiers trying to scale castle walls.
Various types of boiling liquids could also be poured onto besieging enemy soldiers.
When defending a medieval castle, the defenders on castle walls made use of their high position by launching missiles into enemy lines. A crossbow was a highly effective weapon in this regard. Different types of crossbows were used throughout different phases of the medieval era.
The Crossbow became especially popular with castle defenders because it allowed them to wreak havoc on enemy lines from a distance. A good crossbow, when wielded by an expert archer, could shoot as far as 400 yards. This meant that good archers on a castle’s walls could effectively withstand an army far larger than their number.
Towards the mid-phase of the medieval period, castle walls typically included small slits made specifically for crossbow archers to launch their arrows and missiles into an approaching enemy. In some cases, crossbows were also used to launch flaming arrows into enemy lines.
Such lit arrows were typically used to torch the siege engines or any other wooden siege weapons carried by the enemy armies.