. . "Second Bulgarian-Mongol War" . . . . . "a Mongol invasion in 1242" . "establish suzerainty" . . . "Bulgarian Empire" . "Fifth Bulgarian-Mongol War" . . "Mongols invaded Bulgaria" . . "Mongol invasion of 1242" . "Mongols" . . . "Mongol invasion of Serbia" . "1242 invasion of Bulgaria and Serbia" . "devastating Bulgaria" . . . "Mongol invasion of Bulgaria and Serbia" . . "1242 invasion of Serbia" . "Fourth Bulgarian-Mongol War" . . ":Mongol invasion of Bulgaria and Serbia" . . "devastations" . "Mongol Empire invaded" . . "Second Bulgarian Empire" . "Bulgaria" . "Mongol invasion of Bulgaria and Serbia" .