Viking Religion Accidentally Produced Strong Steel Swords
Scandinavians in the Iron Age only had access to bog iron – an impure and soft metal. That put Scandinavians at a disadvantage against neighbors armed and armored with better iron. However, Scandinavian religious beliefs led them, unwittingly, to forge an early version of steel swords. That gave them a literal edge over their opponents. Scandinavians believed that mixing the bones of killed animals with the iron used to forge swords imbued the resultant weapon with the spirit – and strength – of the killed animal. That was mumbo jumbo, but the swords that emerged were pretty strong, nonetheless. It was not because of spirituality, however, but science.
The mixture of sacrificial bones with the iron that went into swords did not imbue the swords with any spiritual powers. However, what Scandinavian smiths did not realize was that the bones, like any organic matter, contained carbon. If you mix carbon with iron, you get a rudimentary form of steel. When they burned coal alongside their low quality bog iron, Scandinavian smiths unwittingly produced bone coal – similar to how burning wood produces charcoal. When modern researchers conducted experiments and 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, and produced a significantly stronger weapon.
