The commercial revolution, kind of 1500s, right around there, I'm not great with years, but basically the Crusades is what made that happen. The Crusades were a holy war that the Christian world had fought against the Muslim world and along that crusade, which is unsuccessful, you get that scarcity thing kick in. When people find out that there's spices and silks and different raw materials or different products around the world within the mannerism system, that breaks up and you start to develop trade routes with the Middle East. And now you have cultural diffusion and the spread of ideas and the mannerism system is going to break up. And when you have trade routes, you have cities develop, so that's going to give a place for serfs to go to make a new life. There's a lot of ideas that flow around economic systems. But basically, as the European world in the 15, 16, 17 hundreds starts to grow and modernize, its need for those scarce resources are going to create a desire to create even more trade routes.