[jmyeet]

So this is a fallacy of seeing historical events through a modern lens.

We know how far the Mongols spread and we have accurate maps but in no way am I convinced that France could possibly conceive of the size and scope of Central Asia in the 11th century.

[gostsamo]

They could conceive that you can go across France in a couple of weeks and that you might need a few months to reach China. What's more, they could see how rich the khan is and that it is much more than their king. And that he has much bigger army. Surprisingly, they were not idiots.