This one should get you out in the shop trying to burn it down. Mysterious steel constructed the UlfBerht and an awesome steel working guy makes high quality steel in a backyard kiln. Making low carbon, low occlusion steel was a lost art between the year 1000 to the 19th century. It turns out a guy can make crucible steel in his back yard.
A Viking carrying an UlfBerht would crush opponents because the steel is so refined.
Watch it on PBS by clicking on the image.