I ran across this video on Tartaria, etc on The Blue channel just today. No affiliation, it's the only video on the channel, been there about a month, and already over 11,000 views. (For better or worse, this Tartaria/Tartary thing is blowing up!) While I can't vouch for its accuracy, as I'm no expert on the subject, it did shake a few ideas loose in my little brain. Perhaps it will likewise shake loose some interesting...

"Tartaria: The Hidden Truth" - essay by Marcia Ramalho