In certain cities, it might have been 25, 30% of the population. Some historians even point to these plagues as destabilizing the Roman Empire. And this is a theme that you'll see often in world history, where if you have a population that doesn't have exposure to something, say smallpox, and all of a sudden they encounter a population that does have exposure, well, that smallpox might wreak havoc. But it wasn't just disease. You also have the spread of ideas and technology and religion. And the two religions that perhaps benefited the most from the early trade along the Silk Route, or the Silk Roads, were Christianity and Buddhism. And Buddhism in particular was very appealing to many of these Silk Road merchants.