If you read into the Mongols and Tatars,
especially from the Chinese perspective, you would be shocked to find out that they were considered Caucasian. The Khan himself was red haired and green eyed, according to multiple sources. Russian histography is also another good source, despite almost a quarter of Russian nobles being of Mongol and Tatar descent, there was hardly any mentions of exotic appearances among them (you would think that dark complexioned, flat nosed and broad cheekbone individuals would painfully stand out amongst a population of blond haired, blue-eyed Russians...!)
A more likely explanation was that the Mongols, since they conquered all of China and Central Asia, simply intermarried with those individuals and were brought back to Mongolia (the epicentre of that short-lived Empire). Which I suppose is a double negative, as while it might be a dubious claim that the Mongols were ''really European", on the other hand, it shows that the Mongols were extremely tolerant (which they were) towards other religions and peoples (at least, after they were done genociding that was).