When we think of Vikings, our minds don’t normally conjure a picture of a miner. So where did the Vikings (and others) get the iron ore to forge their tools and weapons?
As Mats Andersson says on Quora, they literally fished it out of bogs.
As Wikipedia explains, Europeans developed iron smelting from bog iron during the Pre-Roman Iron Age of the 5th/4th–1st centuries BCE, and most iron of the Viking era (late first millennium CE) came from bog iron.
A lot of Scandinavia is bogland. The acidic conditions make iron settle on the bottom of the bog, in big lumps.
Humans can process bog iron with limited technology, since it does not have to be molten to remove many impurities. All you need is wood for charcoal, clay for the construction of bloomery furnaces, and water for processing.
Due to its easy accessibility and reducibility, bog iron was commonly used for early iron production. The Vikings (and early metallurgists) stabbed wooden or metal sticks into the ground to detect larger ore-deposits, then cut and pulled back layers of peat in the bog using turf knives to extract smaller, pea-sized nodules of bog iron.
Iron in the ore is reduced to a spongy iron bloom that stays in the upper part of the furnace while the undesirable elements stream downwards as slag. The bloom must then be consolidated with a hammer to make usable wrought iron. There is some archaeological evidence that lime was added to furnaces to treat silica-rich ores that were difficult to smelt by the bloomery process.
The Ulfberht Swords
However, there is another type of sword used by the Vikings; one that boggles the mind. Besides bog iron swords, some Viking swords were made from a type of steel that wouldn’t be invented until the 18th century: The Ulfberht swords.
As Henley Bradley explains on Quora, for a short period between the 9th-11th century at the height of the Viking age, an unbelievably talented Blacksmith (or group of Smiths) started making the finest steel swords in the medieval world.
Each Ulfberht sword that we have found, is engraved with the name +VLFBERH+. They all date from roughly the same period.
These were not normal swords. They stood apart from all other weapons of the medieval age, being made from a unique steel of such high quality, that they seem to belong to another age entirely.
The blacksmithing craftsmanship put into some of these blades remains a thing of beauty. So far, we have found 170+ Ulfberht Swords, most of them in Scandinavia.
The metallurgy used was far ahead of its time, and resulted in swords that would have been stronger, more resistant to wear or damage, and may possibly have shimmered in the smokey wave-like manner of Damascus Steel.
There is an area of the Indian Subcontinent that produced Wootz steel with very low impurities, and it’s possible that this was the source for Ulfberht and Damascus steel. It appears that steel ingots were purchased by Vikings who regularly traveled to the Middle East to sell slaves captured in the British Isles and Northern Europe. They then supplied a talented blacksmith from Frankia or Scandinavia, who forged the swords in northern Europe for use by Norse/Viking warriors.
Amazingly enough, this type of steel wouldn’t officially be invented until 1704 when Huntsman found a way to make Crucible Steel.
So, whether you’re writing a Medieval drama or time-traveling story featuring a talented Blacksmith who finds himself in Viking times, why not impress your readers with the addition of a Ulfberht sword?