I can go to an ATM machine anywhere in the world, and for the most part, I can put in my ATM card and get access to money. But there's a lot of infrastructure that makes that happen. Today we have telecommunications, we have satellites that help information go back and forth, we have servers that keep track of all of that data. They didn't have that in the Middle Ages. And so you can imagine this is a very powerful idea, that I could deposit money one place, and then I could withdraw it someplace else. And we still don't fully understand how the Knights were able to pull this off. It requires a lot of trust, and how were they able to authenticate the notes of credit at any of these points?