That probably caused some of those varmints, some of those rodents, some of those rats to go scurrying about. And at the same time period you have the Silk Road, which is this transport system between China and Europe. And now it's not as easy as just saying that the rats got on the Silk Road and they were carried into Europe. That's not how it happened. Because the Mongols at that time period had turned to Islam and basically shut the Christians off from the Silk Road. And that basically occurred in Crimea, that was the border. And in Crimea you still had some Italian tradesmen and they were holed up in a city called Kaffa.