Has anyone read Khakhanate by Thomas Lankenau? It's a book about a group of Mongol Ordu that, when the Khanate is collapsing to the Ming Dynasty, make a great trek up north and east across the Bering Straight and into North America. I'm only about halfway through it, but so far they've started absorbing some of the tribes and establishing a new Khanate on North America (the "Khanate of the Blue Sky"). The idea of them going over the Bering is a little far fetched, but their interactions with the different Native Americans is very interesting, especially all of the technological advances (horses, iron tools, Mongol recurve composite bows, gunpowder, etc.) that they have that they're also willing to share with Native Americans that join them--also, the amount of detail shows a great deal of research on the different tribes by the author. Needless to say, when the book ends, the Americas are going to be much better prepared to meet the Europeans!