Here's a site to start with: http://www.worldhistoryplus.com/m/mongolEmpire.html
Now for a little excerpt: "After Guyuk's death, Batu sent Berke, who maneuvered with Tolui's widow, and in the next kuriltai (1253), the Ogodite line was passed over for Mongka, Tolui's son, who was said to be favourable to Nestorian Christianity. The Ogodites did not immediately go into opposition but they retained their Mongolian domains.
Chaghatai died shortly after Ogodai. The Chaghataites, who had previously accepted Guyuk, consented to the succession to Mongka with some reluctance, but on the whole the fraternal Mongol Empire did not disgregate. Mongka had two brothers who were brilliant warlords: Kublai and Hulagu. In the west, Baghdad and Iraq were subjected to Mongol rule in 1256-1258 by Hulagu (Ilkhanid Persia). A secessionist attempt by Baghdad was crushed and the last Abbasid caliph, al Mustasim, was rolled into rugs and trampled to death by horses. The Egyptian Mameluke Sultanate under Baybars contained the Mongol onslaught at Ain Jalut, Syria, in 1260."
I know that doesn't cover it all, but among the Mongolian leadership elite it was commonly the practice for any children to be raised in the religion of the mother!
Today's Mongols in Mongolia may well be predominantly Buddhist, but most of the Mongols back in the 1000-1400 period MOVED OUT OF THAT GODFORSAKEN MISERABLE PLACE and their descendants live all over the Eurasia in many nations.
Remember, these were the first truly modern people and didn't let the little stuff like religion get in the way of tax collection, good communications, a fulfilling sex life, and cheap wine.
Your contempt is misplaced, and it is apparently you who are ignorant of history: a common enough failing in America where even the history of Orthodox Church is little known, and the separated churches of the East, the Monophysites and the Nestorians are remembered if at all only as vague names of obscure doctrinal tendancies.
Yes the Mongols are now overwhelmingly Buddhist, but the post you were replying to was a review of history. A fair portion of the Mongols in the time of Genghis Khan and his immediate successors were Nestorian Christians (converted by missionaries from what is now Iraq). Although Kublai Khan was himself a Buddhist, one of his wives was a Christian, and he sent a Christian monk to Europe in an unsuccessful attempt to secure an alliance against the Muslims.
China had thriving Nestorian monasteries for centuries until, I forget which Emperor launched a persecution which forced conversion to Buddhism.
Want more? Do a Google search for Nestorian and Mongols
at the same time. Such tidbits as rulers of the Black Khitai with names like John, Elias, and George. . .