KING Arthur had one. Royal families lusted after them. They were swords so strong they were deemed magical. Some survive to this day, though only now do we have any inkling of how and where they were forged.

Swords forged of secret steels were the must-have item of Europe’s nobility.

Distinctive. Rare. Powerful.

They even came with nifty brand names.

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But the strangely mottled blades clearly gave their wielders an edge in combat: The impact of these mystical weapons echoes even now in the “Valerian” steel swords of Game of Thrones and the blade “Anduril” wielded by Aragorn in Lord of the Rings.

Unlike common blades, these would not shatter. When swords clashed, the special steel would bite deep into its opponent with scarcely a scratch on its own surface.

It was an edge worth paying a king’s ransom for.

They had to: The swordsmiths guarded their secrets jealously. It was just good business.

Mystic origins

“Damascus” steel was one of the metals only recently surpassed by modern technology. As its name implies, appeared to mainly be produced by Middle Eastern swordsmiths, though they are believed forged from ore mined in India.

Another form was known as “crucible’ steel which produced blades with a distinctive, woodgrain texture (and a nanoscale crystalline structure that enhanced its strength). Though also found in southern Asia, one such “brand” of crucible blade shone brightly from the hip of Vikings and Crusaders.

And they hadn’t stolen it.

Like modern luxury branded products, these blades came with their own logo: Ulfberht.

The distinctly Nordic name had led many to believe the mystic metal was of Viking origin.

It was astonishingly strong. It was not so brittle as to shatter, nor so flexible as to bend. It was also unusually light.

Supporting the Viking origin idea is that most of these swords have been found in northern Europe, though some have been found scattered from Ireland to Spain, and Italy to Croatia.

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Forged between 800 and 1000AD, exactly how such primitive metal workers were capable of matching the fine balance of carbon and iron produced by modern 1600C steel forges long been a mystery.

Until now.

It seems was mostly luck: A handy source of appropriate naturally occurring ore with close to the right mix of elements needed to produce a fine steel.

When the right-quality ore ran out, so too did the blacksmith’s business.

Tracing the source

In October this year, the Institute for Inorganic Chemistry at the University of Hannover examined a Ulfberht-marked blade found in the Weser River in 2012.

The distinctive brand-name Ulfberht was embedded in the sword nickel — a shiny metal resistant to corrosion. Vanity, it seems, was dominant even then.

But Chemist Robert Lehmann determined the steel itself did not come from the far East as with Damascus blades. Instead, this sword had a distinctly high content of manganese. This mineral is common in Europe, though Dr Lehmann was unable to pin-down its source.

An examination of the hilt — while not crucible steel — revealed it to be arsenic-rich iron clearly made from European ores, as was the tin-lead alloy in the handle.

It was the lead in this tin which exposed down where the sword was assembled — if not completely forged — thanks to a recently compiled ‘atlas’ of lead isotopes. It came from a site between the Rhine, Hahn and the Wetterau — in a region called Taunus. This was an area that been exploited since Roman times.

The research revealed two local medieval monasteries had long been associated with weapons manufacture: At Lorsch and Fulda.

Now the search is on to link the name “Ulfberht” — the Mercedes Benz of ancient swordsmiths — to one of these monasteries, and perhaps uncover traces of the forge which manufactured the mysterious blades in such secrecy so long ago.