The enigma of the viking sword Ulfberht: forged with future technologies?
Ulfberht is the name stamped on particular Viking swords used in Scandinavia around the 10th century AD. The forging of these weapons baffles researchers as it was not possible to revisit the technique until at least the Industrial Revolution. Did the Vikings possess superior technology ahead of their time?
Chronicles say that those who wielded an Ulfberht sword had a significant advantage over their enemies. Although similar in size and shape to a common Viking sword, the Ulfberht was much more durable and capable of penetrating armor with ease.
The blade of an Ulfberht was very flexible compared to the weapons of the time, so solid that it easily penetrated wood and steel, thus giving the swordsman the possibility of easily eliminating the enemy. It was owned only by the chiefs and a small elite of warriors.
The characteristic mark that identified her was imprinted on her blade: + VLFBERH + T
The meaning of the word “Ulfberht” is not known. It is the transliteration into Latin characters of the acronym engraved on the blades of these enigmatic swords. The most common hypothesis is that it was the name of the blacksmith who produced them. Others have proposed that it probably consists of the Old Norse word 'Ulfr' (wolf) and 'beraht' (light, shining, luminous).
A 10 century long enigma
Archaeologists have found 171 Ulfberht swords so far, but only a few of these have turned out to be authentic. The oldest dates back to around the year 850.
Only little information is available on the manufacture of these swords. However, what baffles archaeologists is the type of metal used to produce the Ulfberht, such a pure form that they had to wait until the technology made available by the Industrial Revolution, some 900 years later, to reproduce it.
While most medieval weapons were made of soft iron with very little carbon, the steel used to make Ulfberht had a high concentration of carbon and significantly less slag.
In the process of forging iron, the ore must reach its melting point at 1529°C to be liquefied and allow the blacksmith to eliminate impurities. At that point, carbon is added to make the iron much stronger.
The point is that medieval technology did not allow such a high temperature to be reached. Slag was removed by hammering, a much less effective method. Only with the advent of the Industrial Revolution will tools capable of bringing iron to its melting point be developed. The creation of the Ulfberht, therefore, still remains an enigma.
All of the thousands of medieval swords that have been found in Europe were believed to have been made of this inferior metal, at least until Dr. Alan Williams, an archaeometallurgist and consultant to the Wallace Collection at the London museum analyzed the Ulfberht.
“These swords are far better than any made, before or since, in Europe. They must have been extremely valuable to their contemporaries, given their properties,” explains Williams. “They are produced with a metal that I had never seen in a medieval object, neither before nor since. It's something completely different."
“The first thing that strikes you is the absence of these long inclusions of gray slag, which make the metal brittle. The uniformity is much more similar to modern steel than to medieval steel. Furthermore, it has a carbon content approximately three times higher than that produced in the Middle Ages. It's really very strange. I can't find a reason for that,” Williams continues.
The biggest mystery is understanding where the Vikings obtained this knowledge. There is no archaeological evidence of the production of this type of steel in Europe for the next 800 years. Being great travellers, some think that the Vikings learned the technique in the east, perhaps in India.
Even the acronym +ULFBERH+T is a real mystery. “We don't know why it's written there. We are quite perplexed. It's as if they wanted to indicate that we were faced with something of quality, something unique. But Ulfbehrt is actually an enigma,” admits Jon Anders Risvaag of the University of Science of Norway.
