Image from Wiki of Ice and Fire.

Game of Thrones is back, and with it Valyrian steel swords. Magic or otherwise better-than-normal swords are common to fantasy literature, and it got m thinking about the real-life basis for it. There is one, and it doesn’t even require magic: Damascus steel, the scourge of medieval and early modern warfare.

Let’s give credit where credit is due: the idea came from this video that gets into the possibilities of Valyrian steel, which comes at it from the point of view of pure chemistry and metallurgy rather than archeology. So apologies to Ryan Consell.

Let’s start with the properties of Valyrian steel. In the books Valyrian steel is harder, holds an edge better, and lighter than any ordinary steel used in swords or knives (George R. R. Martin isn’t clear as to whether it is ever used for armor, though it isn’t inconceivable).

When Jon turned the sword sideways, he could see the ripples in the dark steel where the metal had been folded back on itself again and again…” (Game of Thrones, chapter 60 [Jon])

This is a strong clue. The folding is known in the business as pattern welding, and Damascus steel was made in just this way. The name comes from the city of Damascus, where the swords were purportedly made. Odds are they were manufactured all over the region and Damascus was just the place where the people selling the swords tended to be from (Europeans who went there were never all that particular about details).

What makes pattern welding so powerful is the folding. Steel of any sort is a combination of iron and carbon. Stainless steel, spring steel and structural steel all have differing amounts of carbon in them depending on what you want from the metal. The amount of carbon is pretty small, usually less than 1 percent, but combine that with other trace elements and you can get an alloy that has whatever properties you’re looking for. In the case of spring steel, for instance, you want something that retains its shape, and for flatware you’d want the metal to resist corrosion.

In the case of swords, you need a metal that is resilient, but will also hold an edge. A sharp sword that is hard but shatters when it hits something isn’t much use. Pure iron, though, is too soft and vulnerable to corrosion. That’s where the pattern welding comes in. By alternating layers of relatively soft, low-carbon steel with layers of higher-carbon steel, you can get the best of both worlds. The quenching (with water, but there are accounts of smiths using other liquids such as oil and even blood) also alters the metal – carbon steel gets harder.

Pattern welding is such a useful method that it was invented independently at least three times. Celts in Europe hit on it sometime around the birth of Christ, and Indian smiths figured it out even earlier than that, probably around 600 BCE. Japanese sword makers used a form of it from an early age as well, and probably got the technique from Chinese smiths around 400 BCE. Pattern welding is labor-intensive, so European smiths seem to have left off the technique by the middle ages, perhaps because homogenous steel weapons were easier to mass-produce. Recall that Europe, like Westeros, was a mass of local kings and petty lords vying for dominance, and that would create pressure to make lots of weapons fast. Whatever the reason, by the time the Crusades are happening the place to get a Damascus steel sword was in the Ottoman Empire and points east.

Damascus steel involved more than technique. The raw material itself was blocks of wootz steel, which was invented in India. Wootz steel was near legendary in its day, and the Indian smiths were renowned the world over for their metallurgical skill. The secrets of making it were lost some time in the 18th or 19th century, but modern archeologists have done a pretty good job of figuring out how it was likely done.

Wootz steel gets its combination of resilience and hardness from trace elements and compounds. One of these is called cementite (Fe3C). Modern researchers think that the traces were due to where the iron was mined and the kind of carbonizing process the Indian metallurgists used. Older accounts speak of the use of specific tree species to be used to make the charcoal used in adding carbon to the iron, and specific mines. There might have been other metals, such as vanadium or cobalt, for instance, that the preindustrial craftsmen would have been unaware of.

Another fascinating piece of evidence for the “secret” of Damascus steel was found in 2006. A team at the Technical University of Dresden found, after examining a blade with an electron microscope, that there were carbon nanotubes in the steel. The nanotubes facilitate the formation of cementite wires, at the nanometer scale, inside the steel.

So how good was a Damascus blade? Legends abound of Damascene blades cutting hairs dropped on them and cutting off limbs with one stroke. I’d not buy the hair splitting trick, but a good blade in the hands of a skilled user can accomplish a lot. (If you doubt that something weighing what a sword does can cut through a limb, pick up a meat cleaver and break down a chicken. Now imagine something that’s twice as heavy smacking into your collarbone. Ouch!).

It’s also important to remember that in warfare, sometimes even a marginal technical improvement means a lot. Damascus blades were expensive to make, but when the European knights met their Ottoman opponents during the Crusades they were pretty (unpleasantly) shocked. That in turn created a market for such blades in Europe. I suspect the Damascus swordsmiths weren’t too unhappy – profits were profits. And while a very skilled smith might be able to repair or re-forge a Damascus blade, it was pretty unlikely that any Europeans would have learned to make them from scratch.

All this fits pretty well with the picture of Valyrian steel: a metal made by a group of artisans whose technique has been lost (or who can only be trained in a city very far away) with properties that seem superior to anything local blacksmiths can match. Even the patterning and the color seem to fit, and there’s no need to invoke magic, or knowledge that a pre-industrial people wouldn’t have.

Of course, the final authority is the man himself, George R. R. Martin. He says the Valyrian freehold used magic, and who are we to say otherwise?

References:
The Mystery of Damascus Blades, by John D. Verhoeven, Scientific American, January 2001.

Carbon nanotubes in an ancient Damascus sabre, Nature, M. Reibold, P. Paufler, A. A. Levin, W. Kochmann, N. Pätzke, D. C. Meyer, November 16, 2006