I would say Tabarestan, but you can see Ming. (persia achieves)
I actually did that w/o MoH, and if the Black Sheep Turks guarantee your independence in their feud with the Timurds (which is what happened in my case) you get pretty much the same result. The silk in Tabarestan helps a lot with going over FL, which I used to attack and vassalize Shirvan, once Qara Qoyunlu decided to give me MA. eventually got an alliance with them as well to split Georgia (that I had to break the moment the Ottomans wardeced them) and while the Timurds tried to take advantage of that, by the time they decided to attack me, I could sustain an army far enough above my FL that I was able to beat theirs in the mountain regions thanks to the massive penalties hordes get there. Once you do that, you're pretty much set, as the Timurds quickly go into a death spiral of revolts thanks to war exhaustion and diminishing Horde Unity... In fact, I spend the last 20-odd years of that achievement fighting
Persia to form Persia, thanks to the fact the game starts with their cores existing.
'Course, that's not going to work in a few weeks when the whole region gets reworked in the next update, but I glad I took the effort to earn it now, will see how it is afterwards.
