The “Ulfberht” swords:
Ignoring the guy they have chopping away in the opener (his technique is terrible, no way I’d let him play with any of my swords), there is a lot of blather in this, right down to saying the guy they found to make the sword is, “one of the few people on the planet who has the skills to unravel the mystery of how the Ulfbehrt was made”. It’s bullshit. Lots of people know how it was made. They talk to several.
The question isn’t how it was done. I can tell you the basics. The question is where it was done, how the steel made it to Scandanavia, why it stopped coming, etc. That the smith they got to take part is good is obvious, but there are a lot of people who could do what he did: sure, in relation to some 6 billion people on the planet, there are only minuscule number who can do it, probably between 20-100,000. I have a knife worked by a guy in Ukraine which, were you to give him the same sort of steel, I’ll wager he could work up as well (into a knife, I doubt he has a market for swords, and so hasn’t bothered to learn the specifics).
If you look at the documentary, the things they make such a big deal of: how to make steel, mumbo-jumbo about, “the bones of one’s ancestors, burnt to char and used to turn iron to steel…” is rubbish. The steel came from elsewhere (perhaps from the same area the swordsmiths of Damascus were getting theirs) and when the supply dried up, the blades stopped being that good.
There is no mystical magical “Steel of Ulfberht”, there is just steel, and it got made into a style of (really solid) sword.