In the medieval period, as with any period in history, the weapons of the day were a product of the available technology and raw materials. Arguably, one of the greatest weapons of the day was the castle, but when one thinks of weapons, the thought is usually of the more offensive devices. To that end, the most popular and perhaps the most frequently discussed weapon is the sword.
Virtually every knight would have a sword. Swords were easy to construct and easy to use. Forged from steel and sharpened, the sword could be used both offensively, to attack, or defensively, to block other attacks. It was also available in many sizes and styles. Knives and daggers were also used and sometimes fashioned from wood or animal bones.
While larger than the sword, axes in the hands of the right warrior, could inflict devastating injuries. Spears were common for attacks at a distance being made of wood or having sharpened tips. Other close quarter combat weapons were the mace, a club of several feet in length with a large square or round block of wood or metal on the end that was sometimes covered with spikes to cause additional injury. The flail was a variation on the mace having a chain attached between the club and the spiked end causing more damage by allowing increased velocity in the attack.
Much of the medieval fighting was in close quarters which made the weapons above ideal. However, fighting at long ranges became more important as time progressed and castle defenses developed. Long and short bows were used. Many a medieval battle saw hundreds of archers raining down arrows on their enemy. By launching the arrows high into the air, they would pick up velocity and cause more damage. From the long bow concept, the crossbow was developed. While a simple concept, the crossbow was one of the most lethal weapons of the day. The crossbow fired a heavy arrow fired that caused terrible damage, even being capable of penetrating a knight’s armor. So destructive was this weapon that the church forbade its use, though few abided this decree. Similar to crossbows, the ballista, an infantry form of the crossbow, saw much use.
Siege engines were also used to attack castles. The trebuchet was a catapult/slingshot hybrid that could hurl huge projectiles to penetrate the walls. Battering rams, catapults, even cannons were used. Greek fire, a mixture of a variety materials was also used, when ignited it would burn in almost any condition, even under water.
By way of defense, knights wore armor and chain mail and carried shields; however, the best defense was to be behind a thick castle wall and to avoid the open field combat.
As with clothing and fashion, wealth dictated the weapon available. Peasants rarely could afford traditional weapons and generally fought with what was at hand - sticks, clubs, tools or their bare hands.
The development of gunpowder forever changed the concept of medieval weapons by making many of them obsolete.