27. The Medieval Scandinavian Magic Mumbo That Accidentally Produced Forged Steel
In the Iron Age, Scandinavians only had access to bog iron – an impure and soft metal. That put them at a disadvantage against neighbors who were 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. Scandinavians believed that to mix the bones of killed 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 swords that emerged 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 realize was that the bones, like any organic matter, contained 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.