    Sentence 4: What year did the  Khwarezmian Empire fall’ to “Genghis  Khan?    Sentence . 2: Various —historicat  secondary sources = Morgan, Chambers,  Grousset - state that. the “Mongol  actually defeated the Bulgars, Chamber:    gars had made-up »  (recently crushed) Russians that they  had beaten the Mongols and driven them  from their territory.              