Here's an idea I might want to use sometime.
A guy is born in China, possibly to a noble house. At a young age, he constitutes part of a hostage exchange with the Mongols/Turks/Huns. For whatever reason (e.g. his birth family gets massacred) the hostage exchange is never reversed, and he grows up on the steppe.
Because he's just that awesome, the guy becomes a leader in one of those occasional massive steppe empires, specifically of the part that moves into Europe (and farther than OTL's Mongols did).
Ultimately, his life takes him from a palace by the Yellow Sea to a siege by the North Sea, with his descendents part of the European nobility by default.
The stinger is that future historians probably would not even equate the fearsome conqueror with the kid hardly attested on the other side of the continent.
