INSPIRATION FOR A NOVEL: THE SECRET OF ULFBERHT SWORDS

In antiquity, the blacksmiths melted iron minerals by burning wood charcoal in furnaces one meter high with an inner chamber of thirty centimeters in diameter, where manually operated bellows were arranged around the forge and forcibly introduced air to increase the heat of combustion.

However, as they could not reach the melting temperature of iron, which is 1535°C, the blacksmiths could not obtain liquid iron to pour into molds; instead, they ended up with a mass of soft iron full of impurities.

During the metal extraction process from minerals, charcoal served the purpose of reaching high temperatures and simultaneously reducing iron oxides from minerals to metallic iron, starting at 700-800°C, when the charcoal and iron combined through a reaction, forming the iron and carbon alloy, which was not yet steel.

As mentioned, a mass of iron contains many impurities, and the blacksmiths obtained little iron and carbon alloy, which was then forged through hot beating to eliminate impurities and compact the mass, thus obtaining soft iron, which, however, lacked strength and could be easily bent.

To obtain quality steel, the blacksmiths should have needed to reach higher temperatures to enrich the soft iron with a percentage of carbon (less than 2%).

Therefore, in Europe, throughout antiquity and the Middle Ages, and even later, until the 19th century, steel could not be obtained in a single process but required various stages of mechanical treatments. However, it did not have such high quality.

Because of that, the soft iron was tempered by suddenly cooling the red-hot artifact in water or oil, but they had to reheat it and cool it down again to avoid brittleness.

The processing then proceeded by heating the obtained steel and mechanically working it through forging, cutting, bending, and more, each time bringing it to temperature for further processing, in a slow and challenging process.

But in this chronicle of ironworking in the 9th century, we find a remarkable exception: the steel of the Ulfberht swords!

These Carolingian swords, which initially the historians believed to have been forged by Viking blacksmiths, actually had a metal structure that, compared to modern instrumentation, had the same characteristics that were achieved only from the 19th century, a thousand years later!

But what was the secret behind this steel and the swords with the inscription Ulfberht forged on the strong of the blade?

The reconstruction made by historians and technicians who were able to analyze the metal and then confirmed by highly skilled modern blacksmiths was that the ancient forgers used the crucible technique, allowing them to reach a higher temperature for the melting of iron while enriching it with the necessary carbon to obtain that prodigious steel.

They placed various raw materials in a high-heat-resistant container: iron ore, charcoal powder, sand, and glass.

The crucible was then sealed and placed in the furnace for a whole day until when they removed it, the iron was semi-liquid and mixed with carbon. In that way, the blacksmith could pour the metal into a mold to obtain a steel ingot directly.

Through the classic process, the blacksmith would obtain from the ingot a blade for hot forging, which they would shape and temper, thus obtaining a prodigious weapon for that time, as its steel had a carbon content three times higher than that of a regular sword of the era.

Warriors fought battles for the possession of these swords. People paid enormous sums for it, and warlords made agreements for it, as reported, for example, in the annals of Saint Bertin, of the request by the Saracens for 150 Ulfberht swords in 869 A.D., as ransom for the release of the Archbishop of Arles.

To medieval warriors, especially those Vikings steeped in mythology and pagan beliefs, this technique and these swords must have had an aura of magic that perhaps, along with the tradition of Celtic legends, gave rise to tales of the famous swords in poems that tell of Excalibur of King Arthur or Durandal of Roland.

In this context, the novel "The Arcane Secret of Ulfbehrt's Legacy" took shape with Arnar, a young Frank raised among the Vikings of Gotland, Alberic, a Benedictine monk from Bremen, and Astrid, a Saxon "witch," involved, along with their antagonists, in solving the mystery of the Ulfberht sword steel, closely guarded by the Frankish rulers, with laws of the death penalty for anyone who would steal its secret, or the swords produced with it in a very important abbey.