The Edge of the World: A Cultural History of the North Sea and the Transformation of Europe

by Michael Pye

It’s hard to overstate just how radical this idea was going to be. It wasn’t just that money made two quite different things into equivalents: a barge full of timber equal to a barge full of salt, say, at least in value. You could take that abstraction, put it down on a small bit of parchment or a tally stick and work with it: calculate, estimate, add, divide and subtract, and, if you were lucky, multiply. Buyer and seller had to have the same idea about what money means: a measure and a concept of value more than a thing of value in itself. Merchants found that out later under Charlemagne when coins were clipped and adulterated and were still supposed to be worth the same. There had to be a way to say how one thing was equal to something quite different and then make calculations: so buying a fish or a glass meant using a kind of equation. A new way of thinking became possible.