In what regions did Latin Christendom expand during the period of the early Mongol expansion?
http://www.google.com/search?q=roman+christendom+expansion&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
Skip the first link and read several of the others.
And
http://www.google.com/search?hl=en&client=firefox-a&hs=jFS&rls=org.mozilla%3Aen-US%3Aofficial&q=early+mongol+expansion&btnG=Search&aq=f&aqi=&aql=&oq=
Read widely and take good notes.