Original:  In the early years of the Mongol empire, the death of the ruling monarchs, Genghis Khan and gedei Khan, immediately stopped the Mongol western campaigns because of the upcoming elections.
Revised:  In the early years of the Mongol empire, the death of the ruling monarchs, Genghis Khan and gedei Khan, immediately stopped the Mongols' western campaigns because of the upcoming elections.
Edit intent: fluency