Medieval swords were primarily made of steel. However, the exact composition of the steel varied throughout the medieval period, and sword-making techniques evolved over time.

Early medieval swords were typically made using a type of steel called "bloomery steel" or "wrought iron." Bloomery steel was produced through a smelting process that involved heating iron ore in a furnace with charcoal. This process produced a material that contained a combination of iron and slag, which was then repeatedly forged, folded, and hammered to remove impurities and create a more homogeneous steel.

As medieval metallurgical techniques improved, swordsmiths began using a higher quality steel known as "crucible steel." Crucible steel was produced by melting together iron and a carbon-rich material in a crucible, resulting in a more uniform and higher carbon content steel.

The swords themselves were typically made by heating and shaping the steel through forging, followed by various processes such as grinding, polishing, and tempering to achieve the desired hardness, flexibility, and sharpness.

It's worth noting that the exact steel-making techniques and composition varied across regions and time periods during the medieval era, leading to different qualities and characteristics in swords. Skilled swordsmiths employed their knowledge and craftsmanship to create swords that were effective, durable, and suited to the needs of the time.