The Ulfberht swords from the Viking Age are world-famous for their quality and intricate forging patterns, a result of well-produced crucible steel known by many as Damascus steel. For the Vikings, it was a valuable prestige weapon and a family heirloom. What sets these swords apart, besides their high quality, is the inscription +VLFBERHT+ or variants of it, which has been interpreted as a signature from the forge or the smith who produced the swords. There are many copies of the swords with other variants of the inscription, which are likely inferior copies of the original — so the inscription probably meant something else. Let's take a closer look!
The swords are believed to have a Scandinavian origin, but Ulfberht was not a Scandinavian name. The name was Carolingian (present-day France); however, we know that the Christians on the continent had declared a trade ban with the pagan Norse, so the swords were probably not produced in the land of the Franks. On top of that, there are no known remains of crucible steel production in Europe from this period, whereas finds from present-day Turkmenistan and Uzbekistan show an enormous production of crucible steel.
Both written and archaeological sources tell of extensive trade with the Samanid Caliphate during the 10th century; it is estimated that more than a million silver dirhams flowed from the caliphate to Scandinavia every year! Arabic writings describe how the Norse (Rus) brought walrus tusks, furs and slaves, to name a few, from the north to the Arab markets in the south, while the Vikings brought silver and steel home to Scandinavia. There are also written sources from Europe telling of swords being transported from Scandinavia southward toward the caliphates.
So the question is: Who had the power and resources to sustain a trade that, by prehistoric standards, was very substantial during the years ca 900 – 1050 AD?
According to Snorri's Heimskringla, Harald Fairhair grew up in England as the foster son of King Athelstan. Besides a Christian upbringing, Harald also learned to use Latin script in the Carolingian style that was popular in England at the time — the same script found on the sword.
Everything therefore points to Harald having established trade in high-quality steel from the caliphate, largely with the help of his monopoly on walrus tusks, which were the height of fashion in the caliphate when it came to sword and knife handles. When the steel arrived in the North, it was probably worked by Scandinavian smiths to create the legendary Ulfberht sword, which was then fitted with a beautifully carved handle of wood, bone or leather.
This could explain why the swords of the very highest quality, the original Ulfberht swords, are found mainly in graves within Harald's kingdom or in rivers near famous battles.
The name Ulfberht together with the crosses could then be a compromise between Christian and Old Norse belief — a Christian would read a Frankish name with crosses, while the Vikings would read "Ulf", which may have referred to the wolves that sometimes accompanied Odin into battle.