Secrets of the Viking Sword

PBS Airdate: October 10, 2012

NARRATOR: The Vikings didn't invent crucible steel. In fact, there's no evidence that anyone in Europe knew how to make it until the industrial revolution in the 18th century. But for more than 500 years before the Ulfberht, warriors elsewhere had been fighting with crucible steel weapons.

Swordsmiths across Central Asia produced some of the greatest swords of all time, known as Damascus steel blades. Curiously, they were made from material similar to the Ulfberht.

ALAN WILLIAMS: Damascus steel is a separate class of crucible steel, which is similar in chemical composition, but the crucible steel was cooled very slowly, so the iron formed large crystals. And with careful forging these large crystals form a surface pattern on the blade.

NARRATOR: These unusual swords exhibited many of the same superior qualities as the Ulfberht, but if the Vikings didn't know how to make crucible steel, then where did they get it?

Clues can be found in artifacts excavated from Viking graves, in Scandinavia, as early as the eighth century.

GUNNAR ANDERSSON: The Buddha was found on an island west of modern-day Stockholm. It originates from India, northeast India. And it tells us, of course, that trades with the Far East existed. The ring is the same thing, there. It's this written inscription that says "Allah."

NARRATOR: Thousands of artifacts from the east have been uncovered from Viking graves. Islamic coins were even commonly traded in Scandinavia.

FREDRIK CHARPENTIER LJUNGQVIST: You could go, mostly by river and lakes, all the way from Lake Mälaren, here in Sweden, to northern Iran. The route was known as the Volga trade route.

The interesting thing is that the most Ulfbehrt swords are dated from exactly the same time when the Volga trade route was open, that is from the early 800s to the mid-1,000s.

I think it's very likely that the steel that you find in the Ulfberht swords originated from Iran. I would guess that you bought it from friendly trading connections in Iran, paid with furs and other Nordic commodities, and took it back on your small ships that you used on the rivers.