8. These Old-Timey Blacksmiths Accidentally Stumbled Into Steel Swords
Scandinavians used to have access only to bog iron – an impure and soft metal. That placed them at a disadvantage against neighbors armed and armored with better iron. However, Scandinavian religious beliefs unwittingly led them to forge an early version of steel swords. That gave them a literal edge over their opponents – something noted when the Vikings suddenly erupted to terrorize the Middle Ages. Scandinavians believed that to mix the bones of animals with the iron used in forging swords was to imbue the resultant weapon with the spirit – and strength – of that animal. That was mumbo jumbo, but the resultant swords were pretty strong, nonetheless. It was not because of spirituality, however, but science.
When Scandinavians mixed sacrificial bones with iron, the swords made from that did not possess any spiritual powers. However, what they did not know was that bones, like any organic matter, contain carbon, and if you mix carbon with iron you get a rudimentary form of steel. When they burned bones alongside their low-quality bog iron, Scandinavian smiths unwittingly produced bone coal – similar to how burning wood produces charcoal. When modern researchers mixed bone coal with bog iron to forge swords, they discovered that the process significantly improved the sword. Carbon from the bones penetrated up to three millimeters deep into the bog iron, which resulted in a significantly stronger weapon.
